5.1.1, (1st topic)

Question 1

what is the smallest part of an element that can exist

Answer 1

an atom

Question 2

what are all things made of

Answer 2

atoms

Question 3

what are atoms of each element represented as

Answer 3

a chemical symbol

e.g O represents an atom of oxygen and Na represents an atom of sodium

Question 4

how many different elements are there

Answer 4

about 100 (118)

Question 5

how are compounds formed

what do compounds contain

Answer 5

from elements by chemical reactions

contain two or more elements chemically combined in fixed proportions

Question 6

what do chemical reactions always involve

Answer 6

the formation of one or more new substances

and often involve a detectable energy change

Question 7

how can compounds be represented

how can compounds be separated into elements

Answer 7

by formulae using the symbols of the atoms from which they were formed

can only be separated into elements by chemical reactions

Question 8

how can chemical reactions can be represented

Answer 8

by word equations or equations using symbols and formulae

Question 9

what is a mixture

what happens to the chemical properties of each substance within a mixture

Answer 9

two or more elements or compounds not chemically combined together

remain unchanged

Question 10

what are 5 ways mixtures can be separated

Answer 10

physical processes such as filtration, crystallisation, simple distillation, fractional distillation, and chromatography.

these physical processes do not involve chemical reactions and no new substances are made

Question 11

what was thought of atoms before the discovery of the electron

what did the discovery of the electron lead to

Answer 11

atoms were thought to be tiny spheres that could not be divided

the plum pudding model of the atom

Question 12

what was the plum pudding model

Answer 12

suggested that the atom is a ball of positive charge with negative electrons embedded in it

Question 13

what were the results of JJ Thompson’s alpha particle scattering experiment

Answer 13

conclusion that the mass of an atom was concentrated at the centre (nucleus)

and that the nucleus was charged

this nuclear model replaced the plum pudding model

discovery of electrons

Question 14

who adapted the nuclear model

and how

Answer 14

Neil Bohr

by suggesting that electrons orbit the nucleus at specific distances, in shells

the theoretical calculations of Bohr agreed with experimental observations

Question 15

when were protons discovered

and how

Answer 15

experiments after Neil Bohr’s adaptions to the nuclear model

led to the idea that the positive charge of any nucleus could be subdivided into a whole number of smaller particles

with each of these particles having the same amount of positive charge

Question 16

how was the existence of neutrons within the nucleus discovered

Answer 16

through experimental work by James Chadwick

Question 17

loosing/ gaining electrons for metals and non-metals

Answer 17

metals always loose electrons

non-metals always gain electrons

Question 18

e.g how does a lithium atom form a lithium ion

Answer 18

when it looses one electron form it’s outer shell

Question 19

relative charge of a proton

Answer 19

+1

Question 20

relative charge of a neutron

Answer 20

0

Question 21

relative charge of an electron

Answer 21

-1

Question 22

how many electrons and protons are in the nucleus of an atom

charge of an atom

Answer 22

number of electrons is equal to the number of protons in the nucleus

atoms have no overall electrical charge

Question 23

what does an element’s atomic number show

Answer 23

number of protons in an atom of an element

all atoms of a particular element have the same number of protons

Question 24

is an element’s atomic number the top or bottom

Answer 24

bottom