Q: Which of the following is the correct formula for calculating atomic mass?

$$\text{Atomic mass} = \text{Number of protons} + \text{Number of neutrons}$$

Question 1

Which of the following best explains why atoms are mostly empty space, yet you cannot walk through walls?

Accepted Answer

Atoms are mostly empty space, but the electromagnetic forces between electrons in your body and those in the wall repel each other, preventing you from passing through.

Question 2

Which subatomic particles are found in the nucleus of an atom, and what are their respective charges?

Accepted Answer

Protons (positive charge) and neutrons (neutral charge)

Question 3

If a carbon atom has 6 protons and 7 neutrons, what is its atomic mass?

Accepted Answer

$$6 + 7 = 13$$

Question 4

Which force is responsible for holding protons and neutrons together in the atomic nucleus?

Accepted Answer

The strong nuclear force

Question 5

What is the main reason electrons do not fall into the nucleus despite their attraction to protons?

Accepted Answer

Electrons have too much energy to be confined to the nucleus

Question 6

Which element makes up the largest percentage of the human body by mass?

Accepted Answer

Oxygen

Question 7

A radioactive isotope decays into its stable form at a fixed rate. What is the term for the time it takes for half of the isotope to decay?

Accepted Answer

Half-life

Question 8

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

Accepted Answer

Using radioactive tracers to image glucose uptake in tissues

Question 9

Which of the following best describes an isotope?

Accepted Answer

Atoms of the same element with different numbers of neutrons

Question 10

If the atomic number of an element is 8, how many protons does it have?

Accepted Answer

$$8$$

Question 11

Which of the following elements is NOT considered a trace element in the human body?

Accepted Answer

Carbon

Question 12

Which of the following statements about electron shells is correct?

Accepted Answer

The first shell can hold up to 2 electrons, and the second shell can hold up to 8 electrons.

Question 13

Which of the following best explains the origin of most elements found in living organisms?

Accepted Answer

They were formed in stars and distributed by supernovae.

Question 14

A scientist is using radiometric dating to determine the age of a rock. If the ratio of parent to daughter isotope is 1:3 and the half-life is 1,000 years, how old is the rock?

Accepted Answer

$$2,000$$ years

Question 15

Which of the following is the correct formula for calculating atomic mass?

Accepted Answer

$$	ext{Atomic mass} = 	ext{Number of protons} + 	ext{Number of neutrons}$$

Question 16

Which of the following best describes the relationship between atomic number and element identity?

Accepted Answer

The atomic number determines the number of protons and thus the identity of the element.

Question 17

Which of the following is a correct statement about the distribution of elements in the human body?

Accepted Answer

Oxygen, carbon, hydrogen, and nitrogen make up over 96% of the human body’s mass.

Question 18

Which of the following best explains why isotopes of the same element behave similarly in chemical reactions?

Accepted Answer

They have the same number of electrons and protons, which determines chemical behavior.

Question 19

Which of the following is the correct order of biological organization from smallest to largest?

Accepted Answer

Atom, molecule, cell organelle, cell, tissue, organ, organism, population, ecosystem, biosphere

Atoms, Elements, and the Chemical Basis of Life

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