Chemistry Corner

The common isotopes of hydrogen have masses of 1 amu, 2amu, and 3 amu. The average atomic mass of hydrogen is 1.00794 amu. This shows that the most common isotope has a mass of

• 1 amu

• 2 amu

• 3 amu

• 4 amu

A new element, unbiennium, has been synthesized. A typical sample contains 22.50 percent Ube–323 and 77.50 percent Ube–325. What is the average mass?

• 324.6 amu

• 323.4 amu

• 324.0 amu

• 325.2 amu

What is the electron configuration of a sulfur atom in the ground state?

• 2–4

• 2–6

• 2–8–4

• 2–8–6

Tags

NGSS.HS-PS1-1

A neutral atom always has an equal number of

• neutrons and electrons

• neutrons and protons

• protons and electrons

• protons, electrons, and neutrons

Above is a Bohr-Rutherford diagram of an element.

Which element could be represented by this diagram?

• calcium

• cadmium

• chlorine

• no known element

Tags

NGSS.MS-PS1-1

Above is a Bohr-Rutherford diagram of an element.

Which is the atomic mass for this element?

• 20

• 40

• 60

Tags

NGSS.MS-PS1-1

How many protons are in U-238?

• 238

• 146

• 92

• 330

How many neutrons are in U-238?

• 238

• 146

• 92

• 330

Tags

NGSS.HS-PS1-8

How many total protons and neutrons are in U-238?

• 238

• 146

• 92

• 330

What element is in the Bohr diagram?

• Na

  Sodium

• C

  Carbon

• S

  Sulfur

• B

  Boron

Tags

NGSS.MS-PS1-1