Important Revision from Year 10

Question 1

molecule

Answer 1

two or more atoms, joined together chemically (can be made up of one more more different types)

Question 2

atom

Answer 2

smallest particle of matter that can exist by itself and take part in a chemical reaction

Question 3

compound

Answer 3

two or more different atoms of different elements chemically joined together

Question 4

mixture

Answer 4

two or more materials combined, but no chemical reaction occuring

Question 5

how do you find number of protons?

Answer 5

atomic number (smaller number) of an element

Question 6

how do you find number of neutrons?

Answer 6

mass number (large number) - atomic number (smaller number)

Question 7

how do you find number of electrons?

Answer 7

same as protons, atomic number (smaller number)

Question 8

element

Answer 8

a pure substance that cannot be broken down into simpler substances. Contains only one kind of atom

Question 9

matter

Answer 9

any physical substance that takes up space

Question 10

why can elements exist as an atom or molecule but compounds can only exist as a molecule

Answer 10

elements can exist on their own because they are made up of only one type of atom. Compounds can only exist as a molecule because it needs two or more different elements chemically combined to exist