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

Question 1

Which subatomic particle determines the atomic number of an element?

Accepted Answer

Proton

Question 2

Given an atom with 17 protons, 18 neutrons, and 17 electrons, what is its mass number?

Accepted Answer

$$35$$

Question 3

Which of the following best defines an isotope?

Accepted Answer

Atoms with the same number of protons but different numbers of neutrons

Question 4

If a neutral atom has 12 electrons, what is its atomic number?

Accepted Answer

$$12$$

Question 5

Which equation correctly calculates the number of neutrons in an atom?

Accepted Answer

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

Question 6

A sample of carbon contains both carbon-12 and carbon-14 isotopes. What do these isotopes have in common?

Accepted Answer

Same number of protons

Question 7

Which of the following elements is represented by the symbol 'Mg'?

Accepted Answer

Magnesium

Question 8

Why are some isotopes radioactive while others are stable?

Accepted Answer

Radioactive isotopes have an unstable ratio of protons to neutrons

Question 9

If an atom has 15 protons, 16 neutrons, and 15 electrons, what is its atomic mass?

Accepted Answer

$$31$$

Question 10

Which of the following statements about electrons is correct?

Accepted Answer

Electrons are found outside the nucleus

Question 11

A neutral atom of sulfur has an atomic number of 16 and a mass number of 32. How many neutrons does it have?

Accepted Answer

$$16$$

Question 12

Which of the following best describes the nucleus of an atom?

Accepted Answer

It contains protons and neutrons

Question 13

If a neutral atom of uranium has a mass number of 238 and an atomic number of 92, how many neutrons does it contain?

Accepted Answer

$$146$$

Question 14

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

Accepted Answer

Photon

Question 15

A neutral atom has 20 protons and 20 electrons. What is the identity of this element?

Accepted Answer

Calcium

Question 16

Which of the following statements is true about the periodic table?

Accepted Answer

Elements are arranged by increasing atomic number

Question 17

A sample contains 17 protons, 18 neutrons, and 17 electrons. Which element is this?

Accepted Answer

Chlorine

Question 18

Which of the following is a correct statement about atomic structure?

Accepted Answer

Protons and neutrons are found in the nucleus

Question 19

If an atom has 11 protons, 12 neutrons, and 11 electrons, what is its mass number?

Accepted Answer

$$23$$

Question 20

Which of the following best explains why isotopes of the same element have different mass numbers?

Accepted Answer

They have different numbers of neutrons

Basic Atomic Structure: Study Notes for Introduction to Chemistry

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