$\text{Mass Number} - \text{Atomic Number}$

Question 1

Which of the following elements is NOT one of the six most abundant elements in living organisms, commonly referred to as CHNOPS?

Accepted Answer

Calcium

Question 2

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

Accepted Answer

$8$

Question 3

Which statement best describes the difference between isotopes of the same element?

Accepted Answer

They have different numbers of neutrons.

Question 4

What is the atomic number of an element equal to?

Accepted Answer

Number of protons

Question 5

If the half-life of Carbon-14 is $5,730$ years, how many years must pass for a sample to decay to $\frac{1}{4}$ of its original amount?

Accepted Answer

$11,460$

Question 6

Which of the following is TRUE about valence electrons?

Accepted Answer

They determine the chemical reactivity of an atom.

Question 7

According to the octet rule, how many electrons does an oxygen atom need to gain to fill its valence shell?

Accepted Answer

$2$

Question 8

Which of the following is a correct description of a radioactive isotope?

Accepted Answer

An isotope with an unstable nucleus that emits energy in the form of rays or particles.

Question 9

A neutral atom of nitrogen has an atomic number of $7$. According to the octet rule, what is the electron distribution in its shells?

Accepted Answer

$2, 5$

Question 10

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

Accepted Answer

It arranges elements based on their chemical properties.

Question 11

How are Carbon-13 and Nitrogen-15 respectively different from the more abundant isotopes Carbon-12 and Nitrogen-14?

Accepted Answer

Each have one extra neutron.

Question 12

Which of the following is NOT a use of radioactive isotopes?

Accepted Answer

Increasing the number of valence electrons in atoms.

Question 13

Which subatomic particle has a positive electric charge and is found in the nucleus?

Accepted Answer

Proton

Question 14

If an atom has 6 protons, 6 neutrons, and 6 electrons, what is its atomic mass?

Accepted Answer

$12$

Question 15

Which of the following best explains why Neon (Ne) is chemically unreactive?

Accepted Answer

Its valence shell is full.

Question 16

Which of the following is TRUE about electron energy shells?

Accepted Answer

Shells closer to the nucleus contain electrons with lower energy.

Question 17

A sample contains three isotopes of carbon: $^{12}C$, $^{13}C$, and $^{14}C$. Which statement is TRUE?

Accepted Answer

They are isotopes.

Question 18

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

Accepted Answer

$	ext{Mass Number} - 	ext{Atomic Number}$

Question 19

Which of the following is a trace element required for life in small amounts?

Accepted Answer

Iron

Question 20

Which of the following statements about atoms is correct?

Accepted Answer

Atoms are made up of protons, neutrons, and electrons.

Atoms, Elements, and Atomic Structure: Foundations for General Biology

Study Guide - Practice Questions