chemistry topic 1 periodic table Flashcards
where is the nucleus and what does it contain?
its in the middle of the atom and contains the protons and neutrons
what’s the overall charge of the nucleus?
positive because of the protons
where are the electrons and what charge are they?
they are around the nucleus in shells and are negatively
what’s the relative mass if a proton?
1
what’s the relative mass of a neutron?
1
what’s the relative mass of an electron?
very small
what is the relative charge of a proton ?
+1
what is the relative mass of a neutron?
0
what is the relative mass of an electron?
-1
what are atoms overall?
neutral ( no charge)
what is charge like in an ion?
the number of protons isn’t equal to the number of electrons
what does the atomic number tell you?
how many protons and electrons there are
what does the mass number of an element tell us?
the total number of protons and neutrons in the atom
how do you get the number of neutrons in an atom?
subtract the atomic number from the mass number
what is an element ?
a substance made up of atoms that all have the same number of protons in their nucleus
if a substance only contains atoms with the same number of protons its call what?
element
what is an isotopes?
different forms of the same element, which have the same number of protons but a different number of neutrons
how do you work out the relative atomic mass of an element?
sum of (isotope abundance x isotope mass number)/ sum of abundance of all isotopes
what are compounds?
substances formed from two or more elements , the atoms of each are in fixed proportions throughout the compound and are chemically bonded together
what does making bonds involve?
giving away, taking or sharing electrons
what is a compound that consists of metal and non metal?
an ion
what does the opposite charges in an ion mean?
they are strongly attracted to each other
what does a compound consist of when it has got non metals in it?
molecules
what type of bonding Is it called when non metals share electrons in a compound?
a covalent bond
just like elements are shown as symbols what are compounds shown as?
formulas
`what is the formula for carbon dioxide?
CO 2
what is the formula for ammonia?
NH 3
what is the formula for water?
H2O
what is the formula for sodium chloride?
NACL
what is the formula for carbon monoxide?
CO
what is the formula for hydrochloric acid?
HCL
what is the formula for calcium carbonate?
CACL2
what is the formula for sodium carbonate?
NA2CO3
what is the formula for sulphuric acid?
H2SO4
in a mixture there is no what?
chemical bond between the different parts of the mixture
how can mixtures be separated?
by physical methods
what happens during chromatography?
draw a little line of pencil then a dot of ink. place in water without the ink touching or it will dissolve the different inks will separate and move up the paper
what is filtration used for?
to separate solids from liquids
what two methods can separate soluble solids from solutions?
evaporation and crystallisation
what happens in evaporation?
heat the solution under a Bunsen burner until crystals start to form ( the solvent has evaporated) and keep heating until dry crystals have fully formed
what happens in crystallisation?
heat them the same as in evaporation however when crystals start to form stop heating the dish and leave it cool. Then filter the crystals out and leave them in a warm place to dry
what 4 steps separate rock salt?
grinding, dissolving, filtering and evaporation
what is simple distillation used for?
to separate a liquid from a solution
what happens in simple distillation?
the solution is heated and the part of the solution with the lowest boiling point evaporates, the vapour condenses and is collected
what is the problem with simple distillation ?
you can only separate things with very different boiling points because if the temperature is higher than the highest boiling point they will mix again
what is fractional distillation?
a more complicated type of distillation used when liquids have similar boiling points
in a fractional column where is the coolest and where is the hottest?
the coolest is at the top and the hottest Is at the bottom
what happens to the liquid with the lowest boiling point in fractional distillation ?
it evaporates first
what happens in fractional distillation when the temperature matches the boiling point of the different solutions?
it will reach the top of the column
what happens to liquids with higher boiling points in fractional distillation?
they start to evaporate but will condense and run back down until the temperature is increased to its boiling point
what did John Dalton describe atoms as ?
atoms where solid spheres and different spheres made up the different elements
when did John Dalton come up with his theory?
at the start of the 19th century
what did JJ Thompson conclude about atoms?
his measurements of charge and mass showed that an atom must contain even smaller, negatively charged particles- electrons
when did JJ Thompson come up with his theory?
1897
what was the sphere ideology replaced with?
the plum pudding model
what does the plum pudding model show?
the atom as a ball of positive charge with electrons stuck in it
who showed that the plum pudding model was wrong and when?
ernest Rutherford in 1909
what did ernest ruthorford do?
scatter positively charged alpha particles at a thin sheet of gold
what did ernest ruthorford expect from the ideas of the plum pudding model?
he expected the particles to pass straight through the sheet of gold or only be slightly deflected
why did Rutherford expect this ?
because the plum pudding model explained that the positive charge was thought to be spread out in each atom
what actually happened when Rutherford fired the particles at the sheet of gold?
some deflected more than expected and some deflected backwards
what theory did Rutherford then come up with?
the nuclear model. any particles that came near the nucleus in the middle would be deflected otherwise they would pass through an empty space between the electrons
what did Niels Bohr suggest?
he suggested that electrons were contained in shells
what did James Chadwick discover?
evidence that there was neutral particles in the nucleus - neutrons
how many electrons are aloud in the first shell and the rest?
2 in the first and 8 in the rest
in the early 1800’s what were elements arranged in?
atomic mass
what two ways did scientists categorise elements in the periodic table?
their physical/ chemical properties and their relative atomic mass
what happened when they were arranged in order of atomic mass?
some were placed in the wrong group
what did Mendeleev do in 1869?
he arranged the table in atomic mass but switched them if properties were similar, he also left gaps for undiscovered elements
where are metals on the periodic table?
left
where are non metals on the periodic table?
right
what are vertical columns called in the periodic table?
groups
what does the group number tell us?
how many electrons are in the outer shell
what happens to reactivity as you go down the group?
reactions become more vigorous
in group 7, what happens to reactivity as you go down?
it decreases
what are the rows called in the periodic table?
periods
what does the period tell us?
how many shells an element has got
when metals react what do they form?
positively charged ions
where are non metals found?
at the far right and top
how do metals to the left react?
they don’t have many electrons to remove
how do metals towards the bottom of the periodic table react?
the outer electrons are far away from the nucleus so the electrostatic attraction is weak
what does it mean when there is a weak attraction to the nucleus?
not much energy is needed to remove the electrons and form positively charged ions
why is it hard to form positively charged ions in non metals?
non metals tend to have lots of electrons to remove In order to get a full outer shell or there outer shell is close to the nucleus therefore there is a strong attraction
what is it easier for non metals to do?
gain electrons and become negatively charged ions
what is the bonds called between two metals?
metallic bonding
all metals are strong but malleable, what does malleable mean?
they can be bent or hammered into shape
do all metals have a high or low boiling and melting point ?
high
what do transition metals normally good at being?
being catalysts
what are group one elements known as ?
alkali metals
what do alkali metals have to be stored in since they are very reactive?
oil
what properties do the alkali metals have ?
they are soft with low density
as the alkali metals go down what happens to their reactivity?
the reactivity increases
why does the reactivity increase as you go down the alkali metals ?
the outer electron is more easily lost as the attraction between the nucleus and the electron decreases because the electron becomes further away the further down the group you go
what do all alkali metals have regarding melting and boiling points ?
lower melting and boiling points
what do alkali metals have a high of?
a high relative atomic mass
what ions do the alkali metals form easily?
1+ ions
what is produced when alkali metals react with water?
they produce metal hydroxides and hydrogen
the amount of energy released from the alkali metals reacting does what as you go down the group?
increase
what happens when group 1 metals react vigorously when heated in chlorine gas ?
they form metal chloride salts
what happens when the alkali metals react with oxygen?
they from different types of metal oxide
what happens when lithium reacts with oxygen?
lithium oxide
what are the differences between transition metals and alkali metals?
group 1 metals are more reactive, less dense, hard and strong compared to transition metals and group 1 metals have lower boiling points
what are the group 7 elements known as ?
the halogens
what happens as you go down the group 7 halogens?
they become less reactive
why does reactivity go down throughout the halogens ?
because its harder to gain an extra electron, because the outer shell is further away from the nucleus
as you go down the halogens what happens to their melting and boiling points?
they get higher
what happens to the relative atomic mas as you go down the halogens?
they get higher
to achieve a full outer shells what do the halogens do?
they share electrons with other non metals via covalent bonding
what do more reactive halogens do to less reactive ones?
displace them
what are group 0?
the noble gases
why don’t noble gases react with much at all?
they all already have a full outer shell
noble gases are single atoms not bonded together, whats the name for this?
monatomic gases
what are all elements in group 0 like at room temperature?
colourless gases
are noble glasses flammable?
no
what happens to the boiling point and relative atomic mass of the noble gases as you go down?
they get higher
what is the increase in boiling point due to?
the increase in number of electrons leads to greater intermolecular forces that need to be overcome
what order do the noble gases?
helium, neon, argon, krypton, xenon, radon
