Isotope Calculations

Two different isotopes have the same number of protons.

• True

• False

Two different isotopes have the same number of neutrons.

• True

• False

Protons have a...

• positive charge

• negative charge

• no charge

Neutrons have a...

• positive charge

• negative charge

• no charge

Electrons have a...

• positive charge

• negative charge

• no charge

Tags

NGSS.HS-PS3-5

How do you find the mass number of an atom?

• # of protons + # of electrons

• # of protons

• # of protons + # of neutrons

• # of neutrons + # of electrons

How do you find the atomic number of an atom?

• # of protons + # of electrons

• # of protons + neutrons

• # of neutrons

• # of protons

Calculate the average atomic mass of lithium, which occurs as two isotopes that have the following atomic masses and abundances in nature: Li-6, 7.30% and Li-7, 92.70%

• 6.867 amu

• 6.312 amu

• 6.411 amu

• 6.927 amu

An element has the following natural abundances and isotopic masses: 90.92% abundance with 20 amu, 0.26% abundance with 21 amu, and 8.82% abundance with 22 amu. Calculate the average atomic mass of this element.

• 20.179 amu

• 20.253 amu

• 20.789 amu

• 20.581 amu

Naturally occurring boron is composed of two isotopes. The percent abundance and the mass of each isotope are listed below:

- 19.9% of the boron atoms have a mass of 10 amu

- 80.1% of the boron atoms have a mass of 11 amu

Calculate the atomic mass of boron

• 10.523 amu

• 10.801 amu

• 10.158 amu

• 10.753 amu