Isotope Calculations

The average atomic mass on the periodic table is found from...

• calculating the weighted average mass of all the isotopes of that element

• Calculating different types of elements together

• calculations the average of all elements in that period together.

• making a guess about how much all the isotopes might wiegh together.

The mass of an element is 15 and the number of protons is 7 how many neutrons does it have?

• 15

• 7

• 8

• 22

Tags

NGSS.MS-PS1-1

An element has two naturally occurring isotopes. One is 10.013 amu and is 19.9% abundant. The other is 11.01 amu and is 80.1% abundant. What is the average atomic mass? What element is it?

• 15.99, Oxygen

• 10.81, Boron

• 10.81, Oxygen

• 15.99, Boron

Which of the following represents isotopes of the same element?

• ₈¹⁸O and ₇¹⁸O

• ₉¹⁹F and ₁₀¹⁹Ne

• ₉¹⁹F and ₉¹⁹Ne

• ₈¹⁶O and ₈¹⁸O

Tags

Isotopes

To calculate average atomic mass, you need

• the atomic mass of each isotope

• the percent abundance of each isotope

• the atomic mass and percent abundance of each isotope

• to find the average of the atomic masses of each isotope

A neutral atom of the isotope ²⁶₁₂Mg would consist of

• 12 protons, 26 neutrons, 26 electrons

• 26 protons, 12 neutrons, 26 electrons

• 26 protons, 14 neutrons, 14 electrons

• 12 protons, 14 neutrons, 12 electrons

Tags

NGSS.MS-PS1-1

Copper exists as two isotopes, ⁶³Cu and ⁶⁵Cu. The relative abundance of each isotope is 69% and 31% respectively.

Calculate the A_r of copper.

• 63

• 65

• 63.6

• 64.4

Which of the following statements is true according to modern atomic theory?

• Atoms of the same element may have different masses.

• Atoms may be divided in ordinary chemical reactions.

• Atoms can never combine with any other atoms.

• Cathode rays are composed of protons..

Tags

NGSS.MS-PS1-5

Isotopes are atoms of the same element that have different

• principal chemical properties.

• masses.

• numbers of protons.

• numbers of electrons.

The average atomic mass of an element is the average of the atomic masses of its

• naturally occurring isotopes.

• two most abundant isotopes.

• radioactive isotopes.

• artificial isotopes.