For an experiment, a student needs to determine how many moles are present in 30.2 grams of Cu(OH)2.

• 3217.38 mol

• 2439.04 mol

• 0.30 mol

• 0.45 mol

Germanium has two common isotopes, 71Rb and 73Rb. If the abundance of 71Rb is 39.0% and the abundance of 73Rb is 61.0%, what is the average atomic mass of germanium?

• 8555.63

• 72.22

• 86.91

• 85.56

A sample of a particular element has a silvery-white color, conducts electricity, and has two valence electrons. This element most likely belongs to which group?

• Alkali metals

• Alkaline earth metals

• Halogens

• Noble gases

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which of these is the electron-dot diagram for Cl₂?

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Tags

NGSS.HS-PS1-2

How many neutrons are present in an atom of zinc in the picture?

• 34

• 64

• 92

• 30

Tags

NGSS.HS-PS1-8

What is the electron configuration of a potassium atom at ground state?

• 1s² 2s² 2p⁶ 3s² 2p⁶ 4s¹

• 1s² 2s² 2p⁶ 3s² 2p⁶ 3d¹

• 1s² 2s² 2p⁶ 3s² 2p⁶ 4d¹

• 1s² 2s² 2p⁶ 3s² 2p⁶ 3d¹⁰ 4s¹

Tags

NGSS.HS-PS1-1

Krypton and Xenon are used in the production of certain types of lights. Which of the following best describes the elements within their chemical family

• highly reactive gases

• mildly reactive solids

• nonreactive gases

• nonreactive solids

Tags

NGSS.HS-PS1-1

How many atoms are present in 186 moles of iridium?

• 3.3 X 10⁴ atoms

• 1.12 X 10²⁶ atoms

• 2.82 X 10^-22 atoms

• 1.97 X 10²⁸ atoms

Element X has three naturally occurring isotopes. The chart contains the isotopes and their percentages. What is the average atomic mass of Element X?

• 6.941 amu

• 24.29 amu

• 20.192 amu

• 35.458 amu

Tags

NGSS.HS-PS1-7

Which of the following diagrams correctly represents the formation of a compound consisting of calcium and fluorine?

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• 
• 
• 

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2