topic 1 - key concepts Flashcards
1
Q
anion-
A
A negatively charged ion, formed when an atom gains at least one eletron
2
Q
atomic number-
A
The number of protons in the nucleus
3
Q
what is Avogadro’s constant?
A
The number of atoms, molecules or ions in a mole of a given substance
4
Q
A
5
Q
describe a physical change
A
easily reversible
no new substances made
6
Q
describe a chemical change
A
not easily reversible
new substances made
