8th Grade review SCIENCE

Positively subatomic particles are located in the:

• electron cloud

• energy level

• nucleus

• proton

The neutron of an atom is located in the _____, and it has a _____ charge.

• nucleus ; neutral

• electron cloud ; positive

• nucleus ; positive

• energy level ; negative

The number of protons and neutron in the nucleus of the atom is called the ____.

• isotope

• ion

• atomic number

• atomic mass

The group in the periodic table tells you what?

• The family it belongs to

• The number of valence electrons

• Number of protons

• Number of outer shells

. _________________ are the most stable because their out energy level is filled and make-up group 18.

• Noble gases

• Metalloids

• Alkali

• inner transition metals

What does the C represent?

• atomic mass

• atomic number

• element name

• chemical symbol

The Modern Periodic Table of Elements is arranged by

• atomic mass

• atomic number

• valence electrons

• number of isotopes

How many elements are on the periodic table?

• 100 elements

• 118 elements

• 200 elements

• 180 elements

What is a reactant?

• The chemical substances that begin the reaction.
• What comes from the reaction.

Why must chemical equations be balanced?

• So that the equation doesn't explode

• The reaction won't happen until it is balanced

• Based on the Law of Conservation of Matter, matter cannot be created or destroyed.

• Based on the Law of Conservation of Energy, energy cannot be created or destroyed.e