Isotope & Average Atomic Mass

An isotope has three forms.  30% have a mass of 4 amu, 20% have a mass of 5 amu and 50% have a mass of 3 amu.  Average atomic mass will be closest to

• 2 amu
• 3 amu
• 4 amu
• 5 amu

Calculate the average atomic mass of silver.

• 106.38649amu
• 111.91896amu
• 107.8677amu
• 121

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?

• 9.012, Beryllium
• 12.011, Carbon
• 6.941, Lithium
• 10.812, Boron

Oxygen has 8 protons. What is oxygen's atomic number?

• 16
• 8
• 15.999
• 0

Tags

NGSS.MS-PS1-1

A neutral atom of Carbon-13 has ________ electrons and _________ neutrons

• 13, 13
• 6, 7
• 7, 7
• 6, 6

Tags

NGSS.MS-PS1-1

Isotopes are atoms of the same element that have the same number of __________ but different number of __________ . Therefore, isotopes of the same element have different masses. 

• protons, neutrons
• protons, electrons
• neutrons, protons
• electrons, protons

Tags

NGSS.HS-PS1-8

The  mass of an atom is located  in the ___________ and the volume of an atom is made of the ____________

• electron cloud, nucleus
• electron cloud, energy levels
• nucleus, electron cloud
• nucleus, neutrons

Tags

NGSS.MS-PS1-1

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

24.1% of all the isotopes of a an element have a mass of 75.23 amu, 48.7% have a mass of 74.61 amu, and 27.2% have a mass of 75.20 amu.
What is the average mass of this element?

• 74.92 amu
• 24.97 amu
• 75.01 amu
• 74.51 amu

Calcium has three different isotopes. One has a mass of 35.00 amu; another has a mass of 41.00 amu; and another has a mass of 40.00 amu. Which isotope is the most abundant of the three?

• 40.00 amu
• 41.00 amu
• 35.00 amu
• impossible to tell