Question 1

Which of the following elements is NOT one of the six most important elements (CHONPS) found in living organisms?

Accepted Answer

Calcium (Ca)

Question 2

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

Accepted Answer

$8$

Question 3

Which statement best describes the octet rule?

Accepted Answer

Atoms tend to gain, lose, or share electrons to achieve eight electrons in their outermost shell.

Question 4

Which type of chemical bond involves the complete transfer of electrons from one atom to another?

Accepted Answer

Ionic bond

Question 5

What is the electron configuration for a sodium (Na) atom, which has an atomic number of 11?

Accepted Answer

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

Question 6

Which of the following molecules contains a polar covalent bond?

Accepted Answer

Water ($H_2O$)

Question 7

Why are noble gases (Group 18) generally unreactive?

Accepted Answer

They have a full valence shell of electrons, satisfying the octet rule.

Question 8

Which of the following best explains why the shape of a molecule is important in biological systems?

Accepted Answer

It affects how the molecule interacts with other molecules, influencing biological function.

Question 9

A water molecule ($H_2O$) has a bent shape due to:

Accepted Answer

The presence of two lone pairs of electrons on the oxygen atom.

Question 10

Which of the following is a trace element required by living organisms?

Accepted Answer

Iron (Fe)

Question 11

What is the main difference between a molecule and a compound?

Accepted Answer

A molecule consists of two or more atoms bonded together, while a compound consists of two or more different elements bonded together.

Question 12

Which of the following best describes a hydrogen bond?

Accepted Answer

A weak attraction between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom.

Question 13

If an atom has 17 protons, 18 neutrons, and 17 electrons, what is its atomic mass?

Accepted Answer

$35$

Question 14

Which of the following best describes van der Waals interactions?

Accepted Answer

Weak attractions between molecules due to temporary dipoles.

Question 15

Which of the following statements about electronegativity is correct?

Accepted Answer

Electronegativity is the ability of an atom to attract electrons in a chemical bond.

Question 16

Which of the following molecules is nonpolar?

Accepted Answer

Methane ($CH_4$)

Question 17

When do electron orbitals hybridize and what shape does the atom gain as a result?

Accepted Answer

When atoms form covalent bonds, orbitals hybridize to form a tetrahedral shape.

Question 18

Which of the following is true about the Bohr model of the atom?

Accepted Answer

Electrons orbit the nucleus in defined energy shells.

Question 19

Which of the following best explains why knowing the distribution of electrons around the nucleus is important in biology?

Accepted Answer

It determines how atoms interact and bond with each other.

Question 20

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

Accepted Answer

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

Ch 2 Outline Atoms, Elements, and Chemical Bonds: Foundations for General Biology

Study Guide - Practice Questions