Masses of Atoms

• Mass Number = Atomic Number + Neutrons
• Mass Number = Atomic Number - Neutrons
• Mass Number = Atomic Number + Electrons
• Mass Number = Atomic Number - Electrons 

Tags

NGSS.MS-PS1-1

Most of the mass in an atom is concentrated in the...

• electrons

• nucleus

• protons

• empty space

How many neutrons would Fe-56 have?

• 56

• 26

• 30

• 33

What is the atomic mass based on?

• Sum of the atomic number and the number of neutrons

• Total number of electrons in an atom

• The number of protons in the nucleus

• Average mass of all the protons plus neutrons of an element

What is the ATOMIC MASS of this Atom?

Mathematical Equivalence

ON

Tags

HS-PS1-1

The element hydrogen has three naturally occurring isotopes.

Which of the following describes the relationship of these isotopes?

Isotopes have (a)   mass numbers, but (b)   number of protons.

• different

• the same

Answer explanation

The isotopes of hydrogen have different mass numbers but the same number of protons, making the correct answers 'different' and 'the same'.

Tags

HS-PS1-1

What is the mass of a carbon atom that has 6 protons, 7 neutrons, and 6 electrons?

• 6

• 7

• 13

• 19

Tags

NGSS.MS-PS1-1

If an atom has a mass of 35.45 and contains seventeen electrons, its atomic number must be?

• 35.45

• 17

• 18

• no idea

Tags

NGSS.MS-PS1-1

Use your understanding of Atomic Mass to complete the Table.

e

f

g

h

6

24

1

5

9

12

63

8

Tags

HS-PS1-1

The atomic mass of an element is _______ of that element.

• the average mass of all an elements isotopes

• the number of protons plus the number of neutrons of an atom

• the number of protons in each atom

• the number of electrons in each atom