chemistry ncfe 2019 review

Which isotope has the greatest number of protons?

• Pa-238

• U-240

• Np-238

• Pu-239

A neutral atom of a certain element has the electron configuration 1s^2 2s^2 2p^6 3s^2 3p^4. How many valence electrons does the atom have?

• 4

• 6

• 11

• 16

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

This equation represents the radioactive decay of a gold isotope. Which choice correctly completes this equation?

• alpha particle

• beta particle

• photon

• neutron

A neutral atom has a ground state electron configuration of 1s^2 2s^2 2p^6 3s^2. The neutral atom becomes an ion during a chemical reaction. Which is the most likely charge of the ion?

• 2+

• 1+

• 2-

• 6-

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

• 2

• 4

• 6

• 8

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.

Which element will form covalent bonds with chlorine?

• carbon

• aluminum

• magnesium

• potassium

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

• london dispersion forces

• hydrogen bonding

• dipole-dipole forces

• covalent bonding

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

• CrO

• CrO2

• Cr2O3

• Cr3O2