4 Chemistry Basics

Question 1

atomic number

Answer 1

the number of protons in an atom

(equal to the number of electrons)

Question 1

compound

Answer 1

atoms of different elements combined in a specific ratio

Question 3

element

Answer 3

a pure substance. All atoms of the same element are exactly alike and have the same mass.

Question 3

electrons

Answer 3

particles floating in the “cloud” of an atom.

They have a negative charge.

Question 5

group

Answer 5

a vertical column of elements in the Periodic Table. There are 18 groups.

Question 6

isotope

Answer 6

an element can have more than one combination of protons and neutrons. Each version is called an isotope.

Hydrogen and Carbon have several isotopes.

Question 7

neutrons

Answer 7

particles in the center or nucleus of an atom.

They have no charge.

Question 8

period

Answer 8

a horizontal row of elements in the Periodic Table.

There are 7 periods

Question 9

protons

Answer 9

particles in the center or nucleus of an atom.

They have a positive charge. (pro = positive)

Question 10

reactivity

Answer 10

The ease and speed with which a substance reacts with other substances.