Elements arranged in horizontal rows on the periodic table are called periods.

• True

• False

The symbol for Chlorine is C.

• False

• True

The maxium number of electrons in the second energy level is 8.

• True

• False

Two isotopes of carbon are carbon-12 and carbon-14. These isotopes differ from one another by two protons.

• True

• False

Tags

NGSS.HS-PS1-8

The sum of the protons and neutrons in an atom is equal to what _____.

• The number of electrons

• The atomic number

• The mass number

• The average atomic mass

All elements except two want how many valence electrons?

• 2

• 18

• 8

• 32

Tags

NGSS.HS-PS1-1

The atomic number of an element will tell you how many protons there are in an atom.

• True

• False

The sixth quark was named the _______.

• Top quark

• Bottom quark

• Up quark

• Down quark

Who was the first scientist to suggest the existence of atoms?

• Dmitri Mendeleev

• Democritus

• Aristotle

• John Dalton

Subatomic particles with a charge of -1.

• Protons

• Neutrons

• Electrons

• Quarks