Question 1

Which of the following statements best describes an atom?

Accepted Answer

An atom is the smallest unit of a chemical element and the smallest unit of matter.

Question 2

Which subatomic particle has a positive charge, a mass of 1 AMU, and is located in the nucleus?

Accepted Answer

Proton

Question 3

What is the atomic number of an element equal to?

Accepted Answer

The number of protons only

Question 4

A neutral oxygen atom has an atomic number of 8 and a mass number of 16. How many neutrons does it have?

Accepted Answer

8

Question 5

How many electrons can the first and second energy shells hold, respectively?

Accepted Answer

First shell: 2, Second shell: 8

Question 6

According to the octet rule, why is neon (Ne) unreactive?

Accepted Answer

Its valence shell is full of electrons.

Question 7

How many electrons does an oxygen atom need to fulfill the octet rule by filling its valence shell?

Accepted Answer

2

Question 8

What is an isotope?

Accepted Answer

Atoms of the same element with different numbers of neutrons.

Question 9

Carbon-13 and Carbon-14 are isotopes of carbon. How do they differ from Carbon-12?

Accepted Answer

Each has an extra neutron.

Question 10

A radioactive isotope has a half-life of 5,730 years. How many years must pass for a sample to break down to 1/4 of its original amount?

Accepted Answer

$$11,460$$

Question 11

Which of the following is NOT a use of radioactive isotopes?

Accepted Answer

Increasing the stability of atoms in living organisms.

Question 12

Which of the following best describes a covalent bond?

Accepted Answer

An interaction between two atoms resulting from the sharing of electrons.

Question 13

What makes a covalent bond nonpolar?

Accepted Answer

The bonded atoms share electrons equally.

Question 14

If a covalent bond is polar, what is true about the atoms involved?

Accepted Answer

One of the atoms has a partial negative charge.

Question 15

Which of the following is a weak non-covalent chemical bond commonly found in biology?

Accepted Answer

Hydrogen bond

Question 16

What is the main difference between an anion and a cation?

Accepted Answer

An anion is negatively charged due to gaining an electron, while a cation is positively charged due to losing an electron.

Question 17

Which of the following statements is true of ALL atoms that are anions?

Accepted Answer

The atom has more electrons than protons.

Question 18

What type of bond is formed by the electrical attraction between oppositely charged ions?

Accepted Answer

Ionic bond

Question 19

When are atoms most stable?

Accepted Answer

When the valence shell is completely full of electrons.

Question 20

Which property of the bond between a hydrogen atom and an oxygen atom in a water molecule makes it a polar bond?

Accepted Answer

Oxygen is more electronegative than hydrogen.

Atoms, Elements, and Chemical Bonding: Foundations of Chemistry

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