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

Question 1

Which subatomic particle determines the atomic number of an element, and how is the atomic number represented in the periodic table?

Accepted Answer

Proton; it is the number shown above the element symbol

Question 2

Given the atomic number ($Z$) and atomic mass ($A$) of carbon as $Z = 6$ and $A = 14$, how many neutrons does the isotope $^{14}C$ have?

Accepted Answer

$8$ neutrons

Question 3

Which of the following best describes a polar covalent bond?

Accepted Answer

A bond where electrons are shared unequally, resulting in partial charges on atoms

Question 4

What is the molecular formula for methane, and how many total electrons are shared in its covalent bonds?

Accepted Answer

CH$_4$; 8 electrons

Question 5

If an atom has 11 protons, 12 neutrons, and 10 electrons, what is its net charge and what is the name of this ion?

Accepted Answer

Net charge: $+1$; cation

Question 6

Which statement correctly describes the difference between an isotope and an ion?

Accepted Answer

Isotopes have different numbers of neutrons; ions have different numbers of electrons

Question 7

Which of the following molecules is an example of a nonpolar covalent bond?

Accepted Answer

CH$_4$

Question 8

Using the periodic table, what is the electron configuration for a neutral oxygen atom?

Accepted Answer

$1s^2\ 2s^2\ 2p^4$

Question 9

Which of the following best explains why water (H$_2$O) is a polar molecule?

Accepted Answer

Oxygen attracts electrons more strongly than hydrogen, creating partial charges

Question 10

What is the total number of valence electrons in a molecule of carbon dioxide (CO$_2$)?

Accepted Answer

$16$ valence electrons

Question 11

Which type of chemical bond is formed when sodium (Na) reacts with chlorine (Cl) to form NaCl?

Accepted Answer

Ionic bond

Question 12

A radioactive isotope of carbon ($^{14}C$) is used in medical imaging. What makes $^{14}C$ radioactive compared to $^{12}C$?

Accepted Answer

$^{14}C$ has more neutrons, making it unstable

Question 13

Which of the following statements about hydrogen is correct?

Accepted Answer

Hydrogen has one proton and one electron

Question 14

How many protons, neutrons, and electrons are present in a neutral atom of $^{14}C$?

Accepted Answer

6 protons, 8 neutrons, 6 electrons

Question 15

Which of the following best describes the role of valence electrons in chemical bonding?

Accepted Answer

Valence electrons are shared or transferred to form chemical bonds

Question 16

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

Accepted Answer

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

Question 17

Which of the following statements about molecules is true?

Accepted Answer

A molecule is formed when two or more atoms bond together

Question 18

Which of the following best explains why ionic bonds are considered medium strength compared to covalent bonds?

Accepted Answer

Ionic bonds involve the transfer of electrons, which can be disrupted in water

Question 19

Which of the following is a real-world application of isotopes in medicine?

Accepted Answer

PET imaging uses radioactive isotopes to track movement of molecules

Atoms, Elements, and Chemical Bonds: Foundations for General Biology

Study Guide - Practice Questions