Atomic Theory Review

Compared to an atom of C-12, an atom of C-14 has a greater

• number of electrons

• number of protons

• atomic number

• mass number

Which change occurs when an atom in an excited state returns to the ground state?

• energy is emitted

• energy is absorbed

• the number of electrons decreases

• the number of electrons increases

Which statement describes the structure of an atom?

• The nucleus contains positively charged electrons.

• The nucleus contains negatively charged protons.

• The nucleus has a positive charge and is surrounded by negatively charged electrons.

• The nucleus has a negative charge and is surrounded by positively charged electrons.

Tags

NGSS.MS-PS1-1

What is the overall charge of an ion that has 12 protons, 10 electrons, and 14 neutrons?

• 2-

• 2+

• 4-

• 4+

Which notations represent hydrogen isotopes?

• 
• 
• 
• 

Isotopes of an element have a different

• number of electrons

• number of protons

• atomic number

• mass number

Tags

NGSS.HS-PS1-8

The atomic number of an atom is always equal to the total number of

• neutrons in the nucleus

• protons in the nucleus

• neutrons plus protons in the atom

• protons plus electrons in the atom

What is the number of electrons in an atom of scandium?

• 21

• 24

• 45

• 66

Tags

NGSS.HS-PS1-1

Which electron transition in an excited atom results in a release of energy?

• first shell to the third shell

• second shell to the fourth shell

• fourth shell to the third shell

• third shell to the fourth shell

An orbital of an atom is defined as the most probable location of

• an electron

• a neutron

• a positron

• a proton