Atomic structure and the periodic table Flashcards
What is the plum pudding model?
that an atom is a sphere of positive charge, with negatively charged electrons in it
Describe how the results of the alpha scattering experiment lead to the new nuclear model…
1) used a a thin sheet gold foil
2) fired alpha particles at the gold foil
3) most of the particles passed through the foil but some bounced back
What is the charge of alpha particles?
positive
How did the alpha particles going through the foil go against the plum pudding model?
It showed that atoms are mainly empty space.
How did the alpha particles deflecting go against the plum pudding model?
It showed that the centre of the atom must have a positive charge.
How did the alpha particles bouncing back go against the plum pudding model?
It showed that the centre of an atom has a great deal of mass.
What did Neil Bohr suggest?
electrons orbit the nucleus at specific distances.
What did James Chadwick discover?
nucleus also contained neutral particles.
What is the relative charge and mass of a protein?
+1. 1
What is a relative charge and mass of a neutron?
- 1
What is a relative charge and mass of a electron?
-1. very small
What is the smaller number on the periodic table?
the atomic number
What does the atomic number tell us?
tells us the number of protons and electrons
What is the larger number on the periodic table?
mass number
What does the mass number tell us?
number of protons and neutrons added together
How do we calculate the number of neutrons?
mass number - atomic number = number of neutrons
What are isotopes?
atoms of the same element with different number of neutrons.
What are ions?
an atom that has lost or gained electrons, so therefore have an overall charge.
What is the atomic mass?
weighted average number of neutrons.
What is the equation to calculate the relative atomic mass?
(mass number of isotope 1 x percentage) + (mass number of isotope 2 x percentage) / 100
What is an element?
all of the atoms are the same.
What is compound?
2 or more atoms chemicaly combined.
What is a mixture?
different elements or compounds.
How do we separate a compound?
chemical reaction
How do we separate a mixture?
different separating tequniches
What is a molecule?
any elements chemically combined.
What does the amount of protons in a nucleus tell us?
the amount of positive charge in a nucleus.
What does filtration separate?
insoluble solid from a liquid.
What does insoluble mean?
the solid will not dissolve in a liquid.
Describe the method for filtration…
(hint 5 steps)
1) place filter paper into filter funnel
2) pour mixture into filter paper
3) liquid passes through the tiny pores of the fitler paper
4) solid does not pass through the filter paper
5) liquid is now separate from solid.
What equipment do you need in filtration?
1) filter funnel
2) filter paper
3) conical flask
What is the filtrate?
a liquid which passes through the filter paper.
What does cyrstalisation separate?
soluble solid from a solid.
What does soluble mean?
dissolves in liquid.
Describe the method for cyrstalisation…
1) leave solution in beaker for a couple of days.
2) water will evaporate
3) this will behind crystals
How can we make crystallisation happen faster?
heating our solution to evaporate the water
what is the problem with heating our solution during crystalisation?
certain chemicals will break down.
State the two stages of simple distillation?
evaporate the liquid by heating –> vapour –> condense the vapour back into liquid by heating
What is the point of simple distillation?
keeps the dissolved solid and the liquid
Describe the method for simple distillation…
(7 steps)
1) heat the solution until it boils (bunsen burner)
2) liquid starts to evaporate turning into vapour
3) vapour rises up glass tube
4) thermometer reading increases
5) vapour passes through the condenser and condenses because where circulating cold water around it
6) turns into a liquid and collected in water
7) left with crystals in flask and water in the beaker
state the equipment used for simple distillation…
1) flask
2) glass tube
3) glass tube surrounded by a condenser
4) thermometer
What are the group 0 elements called?
noble gases
Are the noble gases unreactive or reactive?
unreactive
Why are the noble gases unreactive?
they have a full outer shell
At room temperature what state are the noble gases?
gases
As we go down the noble gases what happens to their boiling point?
they increase
When metals react do they lose or gain electrons?
lose electrons
What type of ions to metals form?
positve
What is Group one of the periodic table called?
alkili metals
How do group one metals react with oxygen?
rapidly (as they go down)
How do group one metals react with chlorine?
rapidly
Describe the reaction of lithium with water…
reacts rapidly
produces effervence and fizzes –> gas
makes an alkaline gas
Describe the reaction of sodium with water…
fizzes
reacts more quickly than lithium
Describe the reaction with pottasium…
gas produced
extremely rapid
Why is pottasium more reactive than sodium?
loses electron more easily –>
1) radius of an atom increases (greater distance between positive nucleus and negative electron)
2) shielding decreases the attraction between the nucleus and outer electron –> elements have more electrons in internal energy levels.
What is shielding?
the outer electron is repelled by electrons in the internal energy levels
What is group 7 called?
halogens
Are group 7 non metals or metals?
non metals
What is a covalent bond?
a shared pair of electrons
