periodic table definitions

Question 1

element

Answer 1

a pure substance that cannot be broken down into a simple chemical substance by any physical or chemical means

Question 2

compund

Answer 2

a pure substance composed of two or more elements that are chemically joined in fixed proportions

Question 3

atom

Answer 3

empty sphere with a tiny dense nucleus

Question 4

molecule

Answer 4

a group of atoms bonded together in fixed proportions

Question 5

atomic number

Answer 5

the number of protons and electrons in the nucleus of an atom

Question 6

atomic mass

Answer 6

the average mass contained in an atom

Question 7

isotopes

Answer 7

different forms of the same element that are identified except they have different number of neutrons

Question 8

ionic bond

Answer 8

when an electron is given to the other atoms in the bond, oppositely charged ions: metals and non-metals

Question 9

covalent bond

Answer 9

when atoms share electrons: non-metals and non-metals

Question 10

ion

Answer 10

when an atom gains or loses electrons

Question 11

valence electrons

Answer 11

the number electrons in the outer shell