Question 1

Which of the following statements best describes the difference between an element and a compound?

Accepted Answer

An element is a substance that cannot be broken down by chemical reactions, while a compound consists of two or more elements in a fixed ratio.

Question 2

What determines the identity of an atom?

Accepted Answer

The number of protons in its nucleus

Question 3

Which element makes up the largest percentage of body mass in humans?

Accepted Answer

Oxygen

Question 4

If a carbon atom has 6 protons and 8 neutrons, what is its mass number?

Accepted Answer

$$14$$

Question 5

Which subatomic particle is responsible for the negative charge in an atom?

Accepted Answer

Electron

Question 6

What is the main reason that elements with a full valence shell are chemically inert?

Accepted Answer

Their outermost electron shell is complete, so they do not tend to form bonds.

Question 7

Which of the following best describes an isotope?

Accepted Answer

Atoms of the same element with different numbers of neutrons

Question 8

What type of bond is formed when two atoms share a pair of valence electrons?

Accepted Answer

Covalent bond

Question 9

Which of the following molecules contains a polar covalent bond?

Accepted Answer

H$$_2O$$

Question 10

What is the charge of a sodium ion (Na) after it transfers an electron to chlorine?

Accepted Answer

$$+1$$

Question 11

Which of the following best explains why table salt (NaCl) forms crystals?

Accepted Answer

Na$$^+$$ and Cl$$^-$$ ions are arranged in a repeating pattern due to ionic bonds.

Question 12

Which of the following is true about hydrogen bonds?

Accepted Answer

They occur when a hydrogen atom covalently bonded to one electronegative atom is attracted to another electronegative atom.

Question 13

A radioactive isotope of carbon has 6 protons and 8 neutrons. What is its atomic number and mass number?

Accepted Answer

Atomic number $$6$$, mass number $$14$$

Question 14

Which of the following best describes electronegativity?

Accepted Answer

The attraction of an atom for the electrons in a covalent bond

Question 15

Which of the following is a consequence of unequal sharing of electrons in a polar covalent bond?

Accepted Answer

The molecule has partial positive and negative charges.

Question 16

Which of the following is NOT a subatomic particle found in atoms?

Accepted Answer

Dalton

Question 17

If an atom has 7 protons, 7 neutrons, and 7 electrons, what element is it?

Accepted Answer

Nitrogen

Question 18

Which of the following best describes a cation?

Accepted Answer

A positively charged ion

Question 19

Which of the following is the correct molecular formula for formic acid?

Accepted Answer

CH$$_2O$_2$$

Question 20

Which of the following statements about atomic mass is correct?

Accepted Answer

Atomic mass is the sum of protons and neutrons in the nucleus.

Chapter 2: The Chemical Context of Life – Study Notes

Study Guide - Practice Questions