topic 1 - atomic structure and the periodic table: a simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes

Question 1

what is an atom?

Answer 1

the smallest part of an element that can exist.

Question 2

what is a compound?

Answer 2

two or more elements chemically combined in fixed proportions, they can only be seperated by chemical reactions.

Question 3

what is a mixture?

Answer 3

two or more elements not chemically combined together, they can be seperated by physical processes such as filtration, crystallisation, simple distillation, fractional distillation and chromatography

Question 4

what is filtration?

Answer 4

a process used to separate solids from liquids or gases using a filter medium that allows the fluid to pass through but not the solid.

Question 5

what is crystallisation?

Answer 5

a separation technique used to separate a solid that has dissolved in a liquid and made a solution. The solution is warmed in an open container, allowing the solvent to evaporate, leaving a saturated solution.

Question 6

what is simple distillation?

Answer 6

simple distillation is used to separate a solvent from a solutionby heating and cooling. It is useful for producing water from salt solution. There must be a large difference in boiling point between the solute and solvent.

Question 7

what is fractional distillation?

Answer 7

used to separate different liquids from a mixture of liquids by heating and cooling. Liquids must have different boiling points, but they can be closer than in simple distillation.

Question 8

what is chromatography?

Answer 8

used to separate mixtures of soluble substances.

Question 9

what discovery led to the the plum pudding model of the atom and what did this design suggest?

Answer 9

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

Question 10

describe the nuclear model of the atom.

Answer 10

the mass of the atom was concentrated at the centre (nucleus) and the nucleus was charged. It replaced the plum pudding model.

Question 11

why did the results of the alpha particle scattering experiment lead to a change in the atomic model?

Answer 11

the results from the experiment led to the conclusion that the mass of the atom was concentrated at the centre (nucleus) and the nucleus was charged.

Question 12

what is the relative charge of a proton?

Answer 12

+1

Question 13

what is the relative charge of a neutron?

Answer 13

0

Question 14

what is the relative charge of an electron?

Answer 14

-1

Question 15

what TWO things is the number of protons in an atom equal to?

Answer 15

the number of electrons and the atomic number.

Question 16

what is the relative mass of a proton?

Answer 16

1

Question 17

what is the relative mss of a neutron?

Answer 17

1

Question 18

what is the relative mass of an electron?

Answer 18

very small

Question 19

what is an isotope?

Answer 19

atoms of the same element that have a different nu,ber of neutrons?

Question 20

what is the formula to calculate the relative atomic mass of an element given the percentage abundance of its isotopes?

Answer 20

relative atomic mass = [(mass number of isotope 1 x abundance) + (mass number of isotope 2 x abundance)] / total number of atoms

Question 21

what is the maximum amount of electrons that can be contained within the first, second and third shells of an atom?

Answer 21

first: 2
second: 8
third: 8