C3 Elements, compounds and mixtures

Question 1

Element

Answer 1

-pure substance containing only one kind of atom
-can not be divided into more smaller form

Question 2

Compound

Answer 2

-pure substance containing two or more kinds of atoms
-combination in fixed ratio)

Question 3

atom

Answer 3

made up of a positively charged nucleus surrounded by negatively charged electrons

Question 4

Mixture

Answer 4

Two or more atoms or compounds physically combined in a random proportion (NOT chemically combined).

Question 5

homogeneous

Answer 5

solute particles are evenly distributed (e.g. sugar and water solution)

Question 6

heterogeneous

Answer 6

Solute particles are not evenly distributed (e.g. sand and water mixture)

Question 7

molecule

Answer 7

when atoms join together (groups of atoms joined together)

Question 8

Why is air a mixture (not oxygen)

Answer 8

It contains two or more pure substances (nitrogen, oxygen, methane, nitrous oxide)

Question 9

define diffusion

Answer 9

the movement of molecules from a region of higher concentration to a region of lower concentration down the concentration gradient

Question 10

describe an ionic bond

Answer 10

the electrostatic attraction between positive metal ions and negative non-metal ions

Question 11

describe a covalent bond

Answer 11

A shared pair of electrons between non-metal atoms

Question 12

relative charge of a proton, neutron and an electron

Answer 12

proton: +1
neutron: 0
electron: -1

Question 12

relative mass of a proton, neutron and an electron

Answer 12

proton: 1
neutron: 1
electron: 1/2000

Question 13

define an isotope

Answer 13

atoms with same number of proton & electrons but different number of neutrons