concept 2 unit 3

Question 1

Atomic number

Answer 1

The atomic number is the number of protons in an atom’s nucleus.

Question 2

mass number

Answer 2

The mass number is the total number of protons and neutrons in an atom’s nucleus.

Question 3

Isotopes

Answer 3

Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons.

Question 4

Average atomic mass

Answer 4

Average atomic mass is the weighted average of all the naturally occurring isotopes of an element.

Question 5

Which number tells you the following;

A>) the number of protons in an element.
B>) the number of protons and neutrons in an element
C>) the number of total electrons
D>) the identity of an element
E>) the most common form of an element

Question 6

explain what it means for an atom to be electrically neutral

Answer 6

An atom is electrically neutral when it has the same number of protons and electrons, so their positive and negative charges cancel each other out.

Question 7

Explain what the two isotopes of the same element have in common and what is different about them, including when an isotope is considered to be the most stable

Answer 7

Isotopes of the same element have the same number of protons and electrons, which means they have the same atomic number and chemical properties. However, they have different numbers of neutrons, so their mass numbers are different. An isotope is considered the most stable when the forces in its nucleus are balanced, meaning it has a ratio of protons to neutrons that keeps the nucleus from breaking apart or changing over time.

Question 8

written in both hyphen and nuclear form, the most common isotope for Ithum

Answer 8

The most common isotope of lithium is lithium-7.

Hyphen form: lithium-7

Nuclear form:
3
7
Li
3
7
​

Li