Question 1

Which of the following elements is NOT one of the SPONCH elements that make up ~98% of body weight in living things?

Accepted Answer

Calcium (Ca)

Question 2

What is the atomic number of an element defined as?

Accepted Answer

The number of protons in the nucleus

Question 3

Electrons in higher energy levels have greater potential energy. Which process in plants directly involves electrons moving to higher energy levels?

Accepted Answer

Photosynthesis

Question 4

Which statement best describes the mass of an electron compared to a proton?

Accepted Answer

The mass of an electron is approximately $$\frac{1}{1800}$$ that of a proton.

Question 5

Which of the following best explains why neon (Ne) is chemically inert?

Accepted Answer

Its valence shell is full, so it does not need to gain or lose electrons.

Question 6

What is the maximum number of electrons that can occupy a single orbital?

Accepted Answer

2

Question 7

Which of the following bonds is the strongest based on bond energy?

Accepted Answer

C≡C triple bond

Question 8

A water molecule (H$$_2O) is $$polar because:

Accepted Answer

Oxygen has a higher electronegativity than hydrogen, creating partial charges.

Question 9

Which of the following is a trace element in the human body?

Accepted Answer

Iron (Fe)

Question 10

What type of bond is formed when one atom donates an electron to another, resulting in oppositely charged ions?

Accepted Answer

Ionic bond

Question 11

Which of the following molecules contains only nonpolar covalent bonds?

Accepted Answer

H$$_2$$

Question 12

If the electronegativity difference between two atoms is greater than 2.0, what type of bond is most likely to form?

Accepted Answer

Ionic bond

Question 13

Which of the following best describes a hydrogen bond?

Accepted Answer

An attraction between a hydrogen atom in one polar molecule and an electronegative atom in another molecule.

Question 14

Which orbital shape is found in the first electron shell of an atom?

Accepted Answer

1s orbital

Question 15

Why does sodium chloride (NaCl) dissolve easily in water?

Accepted Answer

Water molecules stabilize the ions by surrounding them, weakening the ionic bond.

Question 16

Which of the following statements about van der Waals interactions is correct?

Accepted Answer

They are very weak attractions caused by instantaneous dipoles in nonpolar molecules.

Question 17

What is the angle between hydrogen atoms in a water molecule due to its tetrahedral geometry?

Accepted Answer

$$104.5^\circ$$

Question 18

Which of the following best explains the octet rule?

Accepted Answer

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

Question 19

Which element has the highest electronegativity among those most important in biology?

Accepted Answer

Oxygen (O)

Question 20

Which of the following is true about the geometry and polarity of carbon dioxide (CO$$_2$$)?

Accepted Answer

It is linear and nonpolar because the dipoles cancel each other.

Chapter 2: The Chemical Context of Life – Study Notes

Study Guide - Practice Questions