c1 atomic structure

Question 1

daltons atom model

Answer 1

john dalton thought of the atom as a solid sphere that could not be divided into smaller parts his model did not include protons neutrons or electrons

Question 2

the plum pudding model

Answer 2

scientists discovered sub atomic charged particles the first to be discovered were the electrons this led to the plum pudding model of the atom a cloud of positive charge with negative electrons embedded in it protons and neutrons had not yet been discovered

Question 3

alpha scattering experiment

Answer 3

1)scientists fired small positively charged particles at a piece of golf foil only a few atoms thick
2)they expected the alpha particles to travel straight through the gold
3)they were suprised that some of the alpha particles bounced back and many were deflected
4)to explain why the alpha particles were repelled the scientists syggested that the positive charge and mass of an atom must be concentrated in a small place at its center the called this space the nucleus

Question 4

nucleur model

Answer 4

scientists replaced the plum pudding model and suggested that electrons must orbit the nucleus but not at set distances

Question 5

electron shell (bohr) model

Answer 5

niels bohr calculated that electrons must orbit the nucleus at fixed distances these orbits are called shells or energy levels

Question 6

the proton

Answer 6

further experiments provided evidence that the nucleus contained smaller particles called protons a proton has a positive charge

Question 7

the neutron

Answer 7

james chadwick carried out experiments that gave evidence for a particle with no charge scientists called this the neutron and concluded that the portons and neutrons are in the nucleus and the electrons orbit the nucleus in shells

Question 8

elements and compounds

Answer 8

elements are substances made of one type of atom each atom of an element will ahve the same number of protons
compounds are made of different types of atoms chemically bonded together.the atoms in a compound have different numbers of protons

Question 9

mixture

Answer 9

consists of two or more elements or compounds that are not chemically together the substances in a mixture can be seperated using a physical process

Question 10

methods of seperating mixtures

Answer 10

filtration- insoluble solids and a liquid
crystalisation-soluble solid from a solution
simple distillation-solvent from a solution
fractional distillation- two liquids with similair boiling points
paper chromotography- identify substances from a mixture in a solution

Question 11

charges

Answer 11

proton: charge:+1 relative mass:1
neutron: charge:0 relative mass:1
electron: charge: -1 relative mass:0

Question 12

isotopes

Answer 12

atoms of the same element can have a different number of neutrons giving them a different overall mass number the relative mass is the average mass of all the atoms of an element

Question 13

equation for relative mass

Answer 13

(abundance of isotope 1 x mass of isotope 1)+
(abundance of isotope 2 x mass of isotope 2)
/100