Chemistry NCFE

1) Which isotope has the greatest number of protons?

• Pa-238

• U-240

• Np-238

• Pu-239

2) A neutral atom of a certain element has the electron configuration 1s²2s²2p⁶3s²3p⁴. How many valence electrons does the atom have?

• 4

• 6

• 11

• 16

Tags

NGSS.HS-PS1-1

3) What color of light does a hydrogen atom emit when an electron transitions from the n=6 energy level to the n=2 energy level?

• orange

• yellow

• blue

• violet

Tags

NGSS.HS-PS4-3

NGSS.HS-PS4-4

4) The equation below represents the radioactive decay of a gold isotope.

¹⁷⁴ ₇₉ Au →¹⁷⁰₇₇ Ir + ?

Which choice correctly completes this equation?

• alpha particle

• beta particle

• photon

• neutron

Tags

NGSS.HS-PS1-8

5) A neutral atom has a ground state electron configuration of 1s²2s²2p⁶3s². The neutral atom becomes an ion during a chemical reaction. Which is the most likely charge of the ion?

• 2+

• 1+

• 2-

• 6-

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

6) How many electrons are in the outermost energy level of a neutral carbon atom?

• 2

• 4

• 6

• 8

Tags

NGSS.HS-PS1-1

7) The compound sodium chloride is placed in water and separates into ions. What are the correct names for these ions?

• The chloride and sodium ions are cations.

• The chloride and sodium ions are anions.

• The sodium ion is the anion, and the chloride ion is the cation.

• The sodium ion is the cation, and the chloride ion is the anion.

8) Which element will form covalent bonds with chlorine?

• carbon

• aluminum

• magnesium

• potassium

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

9) Which type of bonding or intermolecular forces is/are weakest?

• London dispersion forces

• hydrogen bonding

• dipole-dipole forces

• covalent bonding

10) What is the chemical formula for chromium(III) oxide?

• CrO

• CrO₂

• Cr₂O₃

• Cr₃O₂