What pair of elements have the same number of valence electrons?
a) Li and Na
b) Mg and K
c) Ti and Nb
d) Rb and Zr

Answers

Answer 1

The ans is A.

You need to refer back to the periodic table n find the 2 the is under the same grp.

Answer 2

Answer: its A

Explanation:


Related Questions

How many molecules are there in 0.5 moles of C2H6?

Answers

Answer:

3

Explanation:

Consider the reaction below. 2 Upper N Upper H Subscript 3 (g) Baseline double headed arrow Upper N Subscript 2 (g) Baseline + 3 Upper H Subscript 2 (g). What is the most likely effect to the forward reaction if there is an increase in pressure on this reaction? The reactant surface area increases. The reaction rate decreases. The reaction is not affected at all. The reaction stops completely.

Answers

Answer:

The increase in pressure of the reacting system will increase the formation of NH₃

Explanation:

The given parameters are;

2NH₃ (g) ⇄ N₂ (g) + 3H₂ (g)

The number of molecules in the reactant side of the equation = 2 molecules

The number of molecules in the product side of the equation = 1 + 3 = 4 molecules

Avogadro's law states that equal volume of all gases at a given temperature and pressure contains equal number of molecules

Therefore, given that the number of molecules of the product are twice the number of molecules of the reactant, the volume of the product is twice the volume of the reactant

If the pressure is increased, at constant temperature by Boyles law, the volume will be reduced, favoring the formation of the low volume occupying NH₃

Therefore, the reverse reaction (formation of NH₃) will preferably occur.

Answer:

The answer is B

Explanation:

The other answer is incorrect. The correct Answer is B

Trust Me

Burning 1 kg of coal releases about 3 million joules of energy. If you could use all of the chemical energy to lift another kilogram of coal, how high could you lift it?

Answers

I could lift 3.06 x 10⁵ m high

Further explanation

Energy is the ability to do work. Energy can change from one energy to another

Potential energy is the energy that an object has because of its position

The potential energy can be formulated:

Ep = m. g. h

E = potential energy of an object, joule

m = object mass, kg

g = gravity acceleration, m / s²

h = height of an object, m

energy of coal = 3.10⁶ J

mass = 1 kg

g = 9.8 m/s²

[tex]\tt h=\dfrac{E}{m.g}\\\\h=\dfrac{3.10^6}{1\times 9.8}=3.06\times 10^5`m[/tex]

please helppp this is about to be due

Answers

Answer:

38

Explanation:

An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.

All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other. For example if neutral atom has 6 protons than it must have 6 electrons. The sum of neutrons and protons is the mass number of an atom while the number of protons are number of electrons is the atomic number of an atom.

In given question atomic number is 38 which means number of proton and number of electrons are also 38 because number of protons are electrons are always equal in neutral atom.

How many atoms are there in 10.2 moles of Phosphorous?​

Answers

There are 2.06 x 10²⁴ atoms

Further explanation

The mole is the number of particles (atoms, molecules, ions)contained in a substance

1 mol = 6.02.10²³  particles

Moles can also be determined from the amount of substance mass and its molar mass

number of atoms :

[tex]\tt 10.2\times 6.02\times 106{23}=2.06\times 10^{24}[/tex]

please need asap
An atom with 38 protons and 49 neutrons would be



Strontium-49


Francium-49


Strontium-87


Francium-87

Answers

Answer:

i think it is francium 87 if i fail then i am sorry

Which statement best describes insoluble substances? Insoluble substances remain the same when in water. Insoluble substances become part of the liquid substance. Water does not remain when an insoluble substance is added. Insoluble substances change from solid to liquid states.

Answers

Answer:

Insoluble substances remain the same when in water.

Explanation:

When a substance is regarded as insoluble, it means that the substance remains the same in water.

Soluble substances usually form one continuous phase with water when they are added to water (eg when salt is added to water).

However, when camphor is added to water, it does not form a single phase with water. It remains the same in the water and maintains a separate phase from the water. Hence camphor is an insoluble substance.

#8- please help i suck at this, ill mark brainliest

Answers

Answer:

A.  Synthesis

B.  Combustion

C.  Single-replacement

D.  Decomposition

Explanation:

A:  Synthesis.  Two reactants are combined to form, or synthesize, one product.

B:  Combustion.  This is the general reaction for combustion.  When something combusts, oxygen must be present.  Carbon dioxide and water must also be produced.

C:  Single-replacement. The oxygen from Fe₂O₃ is moved to K to form K₂O.  Only one thing is being moved, or replaced.

D:  Decomposition.  You have one compound that breaks into, or decomposes, into two products.

a.

A una atmósfera de presión (1atm), ¿cuál es el punto de solidificación del agua?

Answers

Answer:

ajansnnddndjsjjenrndndndndndndndnd

Which of the following atoms has the greatest ionization energy?

a.)W
b.)C
C.)d
P.)d

Answers

Answer:

helium

Explanation:

because there are no electrons screening it from the nucleus

⚠️NEED HELP ASAP⚠️What is the oxidation number of nitrogen in (NO3)2
A) +3
B) +1
C+5
D) -5

Answers

Explanation:

its +5 trust me on this hope this helps kiddo

Which example illustrates a chemical change

shredding paper
smashing a soda can
burning wood
chopping wood

Answers

burning wood because heat indicates a chemical change
burning wood since it is changing into a new substance, whereas the other examples are not

I will give brainliest !

Which of the following is NOT an example of how biotic factors interact with abiotic factors in an ecosystem?

A) Plants remove carbon dioxide from the air and add oxygen.
B) Animals cause erosion by digging in the dirt.
C) A lion preys on a herd of gazelle.
D) A lizard raises its body temperature by using heat from the Sun.

Answers

Answer:

C

Explanation:

I had the same answer during school and the teacher said it was correct but if it isnt I'm super sorry

A lion preying  on a herd of gazelle is not an example of how biotic factors interact with abiotic factors in an ecosystem.

What is an ecosystem?

Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.

Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.

Learn more about ecosystem,here:

https://brainly.com/question/1673533

#SPJ6

When copper is bombarded with high-energy electrons, X rays are emitted. Calculate the energy (in joules) associated with the photons if the wavelength of the X rays is 0.154 nm.

Answers

Answer:

E = 12.92 × 10^(-16) J

Explanation:

Formula for energy is;

E = hc/λ

Where;

h is Planck's constant = 6.63 x 10^(-34) J.s

c is speed of light = 3 × 10^(8) m/s

λ is wavelength = 0.154 nm = 0.154 × 10^(-9) m

E = (6.63 x 10^(-34) × 3 × 10^(8))/(0.154 × 10^(-9))

E = 12.92 × 10^(-16) J

The energy associated with the photons of X rays with a wavelength of 0.154 nm is 1.29 × 10⁻¹⁵ J.

When copper is bombarded with high-energy electrons, X rays, with a wavelength of 0.154 nm (λ) are emitted.

We can calculate the energy (E) associated with the photons of these X rays using the Planck-Einstein relation.

[tex]E = \frac{h \times c }{\lambda } = \frac{(6.63 \times 10^{-34}J.s ) \times (3.00 \times 10^{8}m/s ) }{0.154 \times 10^{-9} m } ]= 1.29 \times 10^{-15} J[/tex]

where,

h: Planck's constantc: speed of light

The energy associated with the photons of X rays with a wavelength of 0.154 nm is 1.29 × 10⁻¹⁵ J.

Learn more: https://brainly.com/question/2058557

whose electronic configuration is likely to be acquired by aluminium by chemical reaction​

Answers

Answer:

Explanation:

The configuration notation provides an easy way for scientists to write and communicate how electrons are arranged around the nucleus of an atom. This makes it easier to understand and predict how atoms will interact to form chemical bonds

how can you find a tutor??​

Answers

Depending on what you are doing, virtual, or in school, you can contact your school and you ask them, or you can have your teacher, based on the subject, tutor you.

<3

Answer:

You can find tutors in many ways maybe you can find some apps or

you can also ask any family members who live close and ask them there is many ways :)

It sometimes depends on the subject

Can I have brainliest pleasee

How many atoms are in 75.4 moles of Copper?

Answers

Answer:

No = Avagardro's number = 6.02 x 10^23

No.of atoms = no.of moles x No x atomicity

= 75.4 x 6.02 10^23 x 1

= 453.908 x 10^23 atoms .

7th GRADE SCIENCE FIRDT PERSON MARKED BRAINLIEST

A generator is used to convert ________ energy into ______ energy

Answers

Answer:

An electricity generator is a device that converts a form of energy into electricity. 

Answer:

mechanical to electrical

Explanation:

Analyzing a blood sample usually involves which type of separation method?
screening
distillation
centrifugation
filtration

Answers

The answer would be Centrifugation! How this helps!

Answer:

the answer is b

Explanation:

i just did quizz

A 1250.0g block of silver at 1oC is placed in 2.6g of water vapor at 102oC. What is the equilibrium temperature of the two substances? Specific Heat of Ag is 0.235J/goC

Please answer with work shown

Answers

Answer:

Explanation:

Let final temperature be T .

vapor is at 102⁰C

loss of heat by vapor in turning into water at 100⁰C

= 2.6 x 2 x 1.996 + 2.6 x 2260 = 5886.37 J

loss of heat to lower temperature to T

2.6 x 4.186 x ( 100 - T )

1088.36 - 10.88 T

Total heat loss = 5886.37 + 1088.36 - 10.88 T

= 6974.73 - 10.88 T

heat gain by silver to gain temperature from 1⁰C to T⁰C

= 1250 x ( T - 1 ) x .235 = 293.75 T - 293.75

heat gain = heat loss

293.75 T - 293.75  = 6974.73 - 10.88 T

304.63 T = 7268.48

T = 23.86°C .

What is the product of Na +CaSO4,

Answers

Answer:

Na + CaSO4 = Na2SO4 + Ca

Explanation:

single displacement (substitution)

Question 3 (1 point)
Which of the following best explains the scenario below?
On a summer morning, Mrs. Houser walks barefoot across her paved driveway with
no problem. However, later that afternoon she steps barefoot onto the same
driveway and must quickly run off because the bottoms of her feet feel like they are
burning. (Lesson 3.02-3.04 Thermal Energy)
Choose the best explanation for this scenario:
As the temperature increased
during the day, the particles in the pavement
moved slower and the thermal energy decreased.
As the temperature increased during the day, the particles in the pavement
moved faster and the thermal energy decreased.
As the temperature increased during the day, the particles in the pavement
moved faster and the thermal energy increased.
As the temperature increased during the day, the particles in the pavement
moved slower and the thermal energy increased.
Pls help ASAP

Answers

Answer:

C. As the temperature increased during the day, the particles in the pavement  moved faster and the thermal energy increased.

Explanation:

During the day, the temperature increases and the average kinetic energy of its particles increases. With the increase in kinetic energy, particles start vibrating faster that occupies more space. This increased molecular motion results in the generation of more thermal energy.

Therefore, the thermal energy of an object increases as its temperature increases.

Hence, the correct answer is "C."

Answer: Hello. the correct answer is Option C. As the temperature increased during the day, the particles in the pavement  moved faster and the thermal energy increased.

Explanation:

I Took the K12 Online School Quiz.

What is the volume of a weather balloon that has 39 grams of helium with a density 0.017 g/mL?

Answers

Answer:

The answer is 235.29 mL

Explanation:

The volume of a substance when given the density and mass can be found by using the formula

[tex]volume = \frac{mass}{density} \\ [/tex]

From the question.

density = 0.017 g/mL

mass = 4 g

We have

[tex]volume = \frac{4}{0.017} \\ = 235.2941176...[/tex]

We have the final answer as

235.29 mL

Hope this helps you

A 32.149 mg sample of a chemical known to contain only carbon hydrogen sulfur and oxygen is put into a combustion analysis apparatus yielding 57.271 mg of co2 and 23.444 mg of h2o. In another experiment 22.345 mg of the compound is reacted with excess oxygen to produce 9.656 mg of sulfur dioxide

Answers

Answer:

C₅H₁₀SO₂

Explanation:

From the given information:

The objective is to identify the empirical formula of the compound.

To start with determining the mass of carbon from carbon dioxide; we have:

[tex]Mass \ of \ Carbon = \dfrac{molar \ mass \ of \ C }{molar \ mass \ of \ CO_2}\times mass \ of \ CO_2[/tex]

Mass of carbon = 12/44 × 57.271  mg

Mass of carbon = 0.2727 × 57.271  mg

Mass of carbon = 15.6178 mg

The mass of hydrogen is:

[tex]Mass \ of \ Hydrogen= \dfrac{molar \ mass \ of \ H }{molar \ mass \ of \ H_2O}\times mass \ of \ H_2O[/tex]

[tex]Mass \ of \ Hydrogen= \dfrac{2\times 1.008 }{18}\times 23.444 \ mg[/tex]

Mass of hydrogen = 2.6257 mg

The mass of sulphur is:

[tex]Mass \ of \ Sulphur = \dfrac{molar \ mass \ of \ S }{molar \ mass \ of \ SO_2}\times mass \ of \ SO_2[/tex]

Mass of Sulphur = [tex]\dfrac{32.07}{64.06} \times \dfrac{9.656}{1} \times \dfrac{32.149}{ 22.345}[/tex]

Mass of Sulphur = 6.9550 mg

The Mass of oxygen can now be = mass of (Sample - Carbon - Hydrogen - Sulphur)

= (32.149 - 15.6178 - 2.6257 - 6.9550)g

= 6.9505 g

Recall that:

number of moles = mass/molar mass

Thus:

The moles of C : H : S : O are:

[tex]= \dfrac{15.6178}{12} : \dfrac{2.6257}{1.008} : \dfrac{6.9550}{32.07} : \dfrac{6.9505}{16}[/tex]

= 1 : 2 : 0.2 : 0.4

Divide by the smallest; we have:

= 1/0.2 : 2/0.2 : 0.2/0.2 : 0.4/0.2

= 5 : 10 : 1 : 2

Thus, the empirical formula is = C₅H₁₀SO₂

please help if you can. thank you.​

Answers

Answer:

[tex]a. BaF_{2} \\b. SnCl_{4}\\ c.Cr_{2} O_{3} \\d. FeO\\e. Li_{3} P[/tex]

Explanation:

Hey, just for a quick tip..you can use a cross to determine which ion will have how many atoms. check the image attached.

Sunidhi made a study chart about changes in states of matter. Which headings best complete the chart? X: Solid Directly to Liquid Y: Liquid Directly to Solid X: Liquid Directly to Solid Y: Solid Directly to Liquid X: Heat Is Released Y: Heat Is Absorbed X: Heat Is Absorbed Y: Heat Is Released

Answers

Answer:

The answer is "freezing and melting sublimating x y".

Explanation:

In the given question, the given table name is used as the matter condition, which is freezing or melting sublimation x y, that must be the best headings throughout order to cancel a column of state of matter.

The process goes from the solid-state to a gaseous state, that is achieved by bringing heat into another system.

Answer:

D eng2020

Explanation:

X:heat is absorbed

y: heat is released

The diagrams below represent three phases of matter labeled A,B and C. Which table correctly identifies the phases of matter represented by the diagrams? *

Answers

Answer:

The correct answer is 1

Explanation:

From the above, we will note the following:

Diagram A is liquid because it takes the shape of its container and it also has a specific volume. The particles are not tightly packed.

Diagram B is gas because the particles are freely moving colliding with one another and with walls of the container.

Diagram C is solid because the particles are tightly packed and are not freely moving.

Therefore, Option 1 is the correct answer.

Answer: 1

Explanation: My professor said it was correct

Which is NOT part of the definition of matter

Answers

Answer:

Everything that has mass and takes up space is matter. Every day, you find something usual that either does't have mass or else don't take up space. Those things are non-matter. Basically, any type of energy or any abstract concept is an example of something that does not have matter.

Explanation:

HELP ASAP
solubility lab
can you please do a scatterplot graph with this information
graph a scatterplot using x = temperature ( in degree Celsius and y=sugar dissolved (in grams). Each row will give one point for the graph. Analyza and interpret the scatterplot.​

Answers

Answer:

the bottom part please

Explanation:

A balloon has a volume of 125mL with 10 pumps of gas. The balloon is reduced in volume to 88mL, how much gas is in the balloon?

Answers

Answer:

7.04

Explanation:

i think

Other Questions
Need help please itll mean alot an ill give good rating and brain!!!! Anyone know how to do this? Im stuck PLEASE HELP ASAPSolve the following system of equations.y = 5x 3y = x2 + 3x 2Question 4 options:A) (1,8)B) (0,3)C) (2,7)D) (1,2) pls helpWhich of the following statements reflects the pros and cons of continuous software updating?Continuous software updates serve no real purpose for the consumer; they only secure a profit for technological corporations.Continuous software updates increase security in digital devices; however, the updates can make certain apps obsolete.Continuous software updates make digital products more useful and secure; however, they can lead to more frequent device replacements.Continuous software updates allow multimedia artists to innovate more; however, they slow down the production process. questions in photo pls help me its due tomorrow. Write and equation of a line perpendicular to y=-5x+8 and passes through (10,4) Assignment Compare and Contrast Essay Write a 45 paragraph comparing yourself to Anne Frank. The final draft of your essay should include: A clear, and arguable, thesis statement that relates to the essay prompt. Be sure you have 3 specific similarities/differences listed in your thesis statement. 3 body paragraphs that each feature a supporting claim, evidence(quotes) from the text as support, and only relevant information that contributes to your argument. Use of either the point-by-point or block method of organization. Use of transitions to reflect the method of organization you select. Evidence of revision to improve unity and coherence, as well as to address modifier errors. need something new The Classic Triangle Testing Problem, (Myer's Triangle): A program reads three integer values. The three values are interpreted as representing the lengths of the sides of a triangle. The program prints a message that states whether the triangle is scalene, isosceles, or equilateral. Develop a set of test cases (at least 6 ) that you feel will adequately test this program. (This is a classic testing problem and you could find numerous explanations about it on the internet. I would recommend that you try to submit your own answer, based on your understanding of the topic)Lets define what the three different types of triangle requirements for the sides lengths are:______. To deal with a wartime economic crisis in 1779, Congress urged states to: a. seek loans from friendly European governments. b. allow the free market to operate without regulation. c. adopt measures to fix wages and prices. d. raise taxes on the wealthy. e. establish food banks to distribute food to the needy. The human machine is organized at different levels, starting with the cell and ending with the entire what? Consider the reaction pathway graph below.Which statement best describes this graph?This is an exothermic reaction with a positive Hrxn.This is an exothermic reaction with a negative Hrxn.This is an endothermic reaction with a positive Hrxn.This is an endothermic reaction with a negative Hrxn. If a cell is not ready to divide, it may "take a break" and enter the __________ Phase. What place value is the 5 in the following number, 123.465? earn 100 points!!! If ABC is an isosceles triangle and DBE is an equilateral triangle, find each missing measure. Match each ecosystem with the most correct description of it.TundraDeciduous ForestDesertGrasslandsAlpineFound in the northernmost parts of North America; features limited plant growth, frozen ground, and little precipitationFound in high mountain ranges; supports little to no tree growth; often features poor soil and cold weatherFound in the central United States; also known as the prairie; features very good soil and moderate precipitation that supports some tree growth and a variety of plants and animalsFound in the eastern half of the United States; boasts a variety of trees, plants, and animals; trees lose their leaves in the fall and winter; experiences four distinct seasonsFound in the southwestern United States; features hot temperatures and little rainfall that results in little vegetation and limited animal life 8. The old lady put the dishes in the sink. Change this sentence to passive voice. * What did the romans build to move water How to do p=hdg I dont understand it all please help Show your work: 15x = 0 What rules does Johansson follow in his photography? Which of Johanssons creations did you like the best? Why?