Alchemy Quiz 09

What can the atomic number tell you about a neutral atom? (Check all that apply.)

• number of protons

• number of neutrons

• number of electrons

• mass number

• atomic weight

Answer explanation

The atomic number can tell us the identity of the element, its location on the periodic table, and the number of protons and electrons.

How do you find the mass of an individual atom?

• The number of neutrons minus the number of protons.

• The number of protons plus the number of electrons.

• The number of neutrons minus the number of electrons.

• The number of protons plus the number of neutrons.

Answer explanation

Each proton and each neutron has a mass of one (in atomic mass units). The mass of an electron is so small by comparison that we ignore it when calculating the mass of an atom.

How do you find the number of neutrons?

• The mass number minus the number of protons.

• The number of protons plus the number of electrons.

• The number of protons minus the number of electrons.

• The number of protons minus the average atomic mass.

• The number of protons plus the average atomic mass.

Answer explanation

Mass number = # protons + # neutrons.

If you have a sample of atoms and each atom has twelve protons in its nucleus, which element is it? Name the element (one word, spelled correctly).

Answer explanation

The number of protons is the atomic number, which tells you where to find the element on the periodic table.

Tags

NGSS.MS-PS1-1

What element does the atomic model represent? Name the element (one word, spelled correctly).

Answer explanation

In a neutral atom, the number of electrons and protons will be the same as the atomic number, which you can use to find the element on the periodic table.

Tags

NGSS.MS-PS1-1

The number of protons in a sodium atom is:

• 11

• 12

• 22

• 23

• 34

Answer explanation

The number of protons is the same as the atomic number.

A neutral atom of chromium (Cr) has 24 protons and 28 neutrons. How many electrons will it have?

• 4

• 12

• 24

• 28

• 52

Answer explanation

In a neutral atom, the number of protons is equal to the number of electrons.

What is the atomic number of this atom?

• 5

• 6

• 11

• 16

Answer explanation

In a neutral atom, the number of protons is equal to the number of electrons, and is the same as the atomic number, which can help you find it on the periodic table.

Tags

NGSS.MS-PS1-1

What is the total number of neutrons in an atom of an element with an atomic number of 18 and a mass number of 40?

• 18

• 22

• 40

• 58

Answer explanation

Mass number = # protons + # neutrons.
#Neutrons = mass # - # protons.

Tags

NGSS.MS-PS1-1

What are the atomic number and atomic mass of this atom?

• number 5,
  mass 10

• number 5,
  mass 11

• number 6,
  mass 11

• number 6,
  mass 17

Answer explanation

Atomic number = # protons.

Mass number = # protons + # neutrons.

Tags

NGSS.MS-PS1-1