topic 1 atomic structure Flashcards
what are group 0 elements known as
noble gases
what kind of gases are noble gases at room temp
colourless gases
how many electrons do group 0 or noble gases have on their outer shell
8, a full outer shell- which makes them very unreactive
as noble gases are very unreactive, where are some reactions carried out
in the atmosphere that only contains a noble gas instead of air
what happens to the relative atomic masses of group 0 elements as you go down the group and to the boiling and melting poin
it increases
if an atom has more electrons what does it mean
it means it has a stronger force and a higher boiling and melting point
what are group 7 elements known as
halogens
the halogens form molecules that contain how many atoms
2 atoms such as Cl2
as you go down group 7, what happens
- they become less reactive- its harder to gain an extra electron as the outer shell is further from the nucleus
- have a higher melting and boiling point
what type of compounds do halogen (group 7) make
molecular compounds
what bond does halogens form
covalent bonds as they react with non-metals to gain an extra electron
how are halides formed
when halogen atoms bond with metals (ionic bonding)
a more reactive halogen will ,,,
displace a less reactive halide
what are group 1 elements known as
alkali metals
give 3 properties of alkali (group 1) metals
soft
- light
- have a low density
as you go down the reactivity series of group 1 what happens
- reactivity increases- the outer electron is more easily lost as it gets further from the nucleus. That’s because it is less attracted to the neclus
- melting and boiling points get lower
- relative atomic mass increases
group 1 alkali metals become what type of ions
1+ ions as they lose one electron on their outer shell to form an full shell
finish the equation
“alkali metal+water —->”
metal hydroxide and hydrogen
what happens when alkali metals are reacted with water
-the reactions are vigorous and produce a metal hydroxide and hydrogen gas
as you go down the in the group of alkali metals what happens to the reactions
the more violent the reaction is because the metal is more reactive
what happens when group 1 metals are heated in chlorine gas
they act vigorously and form white salts called metal chlorides
finish the equation
“alkali metal+chlorine —->”
metal chloride
when group 1 elements are reacted with oxygen what do they form
metal oxide
as group 1 metals are shiny and they become a dull grey colour once reacted with oxygen, why does this happen
because a layer of metal oxide is formed on the surface
what type of ions do metals form when they react
positive ions
what type of ions do non-metals produce
negative ions
if atoms have a full outer shell, what does it mean
it means that they are more stable
what properties do metals have (3)
- they are strong (hard to break) but can be bent or hammered into different shapes (malleable)
- great at conducting heat or electricity
- high melting and boiling points
what properties do non-metals have (5)
- dull looking
- more brittle so break easily if you bend it
- not always solids at room temp
- don’ always conduct electricity
- have a low density
in the 1800s how were elements arranged
by atomic mass
as some elements were in order of atomic mass in the 1800s what did it mean for some elements
they were in the wrong group
what did Demitri Menddeleev do in 1869
- ordered them by atomic mass
- put the elements with similar properties in the same group
- some gaps were left for elements that hadn’t been found yet so Mendeleev used them to predict the properties of these elements
what was discovered after Mendeleev made his table of elements
isotopes but they have the same position on the periodic table
how many elements are there
100
