Q: Which of the following is the correct formula for the number of neutrons in an atom?

$$\text{Number of neutrons} = \text{Mass number} - \text{Atomic number}$$

Question 1

Which of the following statements best explains why the nucleus of a potassium atom does not fall apart, despite the repulsive forces between protons?

Accepted Answer

The strong nuclear force is stronger than the electromagnetic repulsion between protons, holding the nucleus together.

Question 2

Given the electron configuration $$1s^2$$ $$2s^2$$ $$2p^6$$ $$3s^2$$ $$3p^5$$, which element is being described?

Accepted Answer

Chlorine

Question 3

Which of the following is the correct definition of a covalent bond?

Accepted Answer

A shared pair of electrons between two atoms.

Question 4

A neutral atom of sodium has an atomic number of 11 and a mass number of 23. How many neutrons does it have?

Accepted Answer

$$23 - 11 = 12$$

Question 5

Which force is responsible for the repulsion between protons in the nucleus?

Accepted Answer

Electromagnetic repulsion

Question 6

Which of the following best describes an optical isomer?

Accepted Answer

A type of stereoisomerism in which the isomers are non-superimposable mirror images of each other around a chiral centre.

Question 7

Which of the following is a correct example of a carboxylic acid functional group?

Accepted Answer

$$\mathrm{COOH}$$

Question 8

What is the maximum number of electrons that can occupy the third energy level (shell) of an atom?

Accepted Answer

$$2 + 6 + 10 = 18$$

Question 9

Which statement about atomic mass is correct?

Accepted Answer

Atomic mass is rarely a whole number because it is the weighted average of all naturally occurring isotopes.

Question 10

Which of the following is a correct example of a redox reaction?

Accepted Answer

$$\mathrm{Cu$$^{2+}$$ + Mg \rightarrow Cu + Mg$$^{2+}$$}$$

Question 11

Which of the following best describes a polymer?

Accepted Answer

A very long molecule made of many smaller molecules (monomers) joined together by covalent bonds.

Question 12

Which of the following is the correct electron configuration for carbon?

Accepted Answer

$$1s^2$$ $$2s^2$$ $$2p^2$$

Question 13

Which of the following statements about valence electrons is correct?

Accepted Answer

Valence electrons are the electrons in the outermost shell of an atom.

Question 14

Which of the following is a property of alkenes?

Accepted Answer

They contain C=C double covalent bonds.

Question 15

Which of the following best explains why larger nuclei (those at the bottom of the periodic table) are more likely to be radioactive?

Accepted Answer

The strong nuclear force cannot hold the nucleons together over a short distance, making them unstable.

Question 16

Which of the following is the correct formula for the number of neutrons in an atom?

Accepted Answer

$$	ext{Number of neutrons} = 	ext{Mass number} - 	ext{Atomic number}$$

Question 17

Which of the following is a correct example of a substitution reaction?

Accepted Answer

A reaction in which a functional group is replaced by another, involving 2 reactants and 2 products.

Question 18

Which of the following is the correct definition of a radical?

Accepted Answer

An atom or molecule that contains an unpaired electron, making it highly reactive.

Question 19

Which of the following is the correct electron configuration for magnesium?

Accepted Answer

$$1s^2$$ $$2s^2$$ $$2p^6$$ $$3s^2$$

Fundamental Atomic Structure and Chemical Principles: Foundations for Organic Chemistry

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