Module 16: L2 ck - Atomic Mass

Which is the sum of protons and neutrons in an atom?

• atomic number

• average atomic mass

• mass number

• atomic mass unit

How do isotopes of an element compare?

• They have different numbers of protons.

• They have different numbers of neutrons.

• They describe different elements.

• They have different atomic numbers.

How many neutrons does an atom of oxygen-15 have. (Atomic number is 8.)

• 7

• 8

• 15

• 16

Tags

NGSS.MS-PS1-1

The mass of an electron is _____.

• equal to the mass of a proton

• negligible

• the mass of the neutrons plus the mass of the protons

• equal to the mass of the nucleus

The element hydrogen has 3 naturally occurring isotopes. Which of the following describes the relationship of these isotopes?

• same mass, different atomic number

• same mass, same atomic number

• different mass, same atomic number

• different mass, different atomic number

the atomic number of yttrium is 39. The atomic mass of one of its isotopes is 89. How many neutrons are in an atom of this isotope?

• 89

• 39

• 50

• 128

Tags

NGSS.MS-PS1-1

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

• the number of electrons in each atom

• the number of protons in each atom

• the average mass of the atoms

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

The _____ of an element is the number of _____ of an atom of that element.

• mass number, neutrons in the nucleus

• atomic mass, electrons in the nucleus

• mass number, protons plus neutrons in the outermost energy level

• atomic number, protons in the nucleus

The atomic number of manganese is 25 and its mass number is 55. How many neutrons does an atom of manganese have in its nucleus?

• 25

• 80

• 30

• 55

Tags

NGSS.MS-PS1-1

_____ are atoms of the same element that have different numbers of neutrons.

• compounds

• ion

• alpha particles

• isotopes