1. c - Atomic structure

Question 1

definition of an atom

Answer 1

tiny particle

smallest part of an element that can exist

Question 2

definition of molecule

Answer 2

groups of atoms

eg. hydrogen H2, nitrogen N”
water H2O , carbon dioxide CO2

Question 3

describe the structure of an atom

Answer 3

consists of a central nucleus composed of protons and neutrons, surrounded by electrons orbiting in shells

Question 4

what is the relative mass and charge of a proton

Answer 4

relative mass = 1

relative charge = +1

Question 5

what is the relative mass and charge of a neutron

Answer 5

relative mass = 1

relative charge = 0

Question 6

what is the relative mass and charge of an electron

Answer 6

relative mass = 1 / 2000

relative charge = -1

Question 7

definition of atomic no.

Answer 7

no. of protons

Question 8

definition of mass no.

Answer 8

total no. of protons and neutron

Question 9

how do you work out no. of electrons

Answer 9

= to no. of protons ( look at atomic no. )

Question 10

definition of isotope

Answer 10

same no. of protons but different no. of neutrons ( = different mass no.)

Question 11

definition of relative atomic mass ( Ar)

Answer 11

1. average mass of all the isotopes of an element
2. tells you how heavy different toms are compared with the mass of an atom of carbom-12 .

so carbon-12 has an Ar of exactly 12

Question 12

how do you work out the relative atomic mass

Answer 12

mass number on the periodic table

Question 13

what are the rules for the number of electrons allowed on each shell

Answer 13

1st shell = 2 electrons
2nd shell = 8 electrons
3rd shell = 8 electrons

Question 14

definition of relative atomic mass ( Ar )

Answer 14

1. way of saying how heavy different atoms are compared with the mass of an atom of carbon-12
2. average mass of all isotopes of an element = has to allow for the relative mass of each isotope and its relative abundance

Question 15

definition of relative abundance

Answer 15

how much there is of each isotope compared to the total amount of the element in the world

can be a ratio, fraction or percentage

Question 16

how do you calculate the relative atomic mass ( Ar ) of an element from isotopic abundances

Answer 16

1. multiply the mass of each isotope by its relative abundance
2. add those together
3. divide by the sum of relative abundances