chapter 16: periodic table Flashcards
why is there an increase in metallic properties as you go down a group?
- going down a group, the size of an atom increases
> valance electrons of an element will be further away from the attractive force of the nucleus
> an element further down the group will lose its valence electrons more easily
what are the physical properties of alkali metals?
- they are soft and can be cut easily
- they have low melting and boiling points
- they have low densities
> eg. lithium, sodium and potassium float on water
how do the metallic properties change down a group?
- there is an increase in metallic properties and a decrease in non metallic properties
- going down a group, the size of the atom increases
> the valence electrons of an element will be further away from the attractive forced of the nucleus
> element further down the group will lose its valence electrons more easily
period number of an element is the same as…
- the number of electron shells
the group number of an element is the same as…
- the number of valence electrons in an element
how do the physical properties of alkali metals change going down group 1?
- the melting and boiling points decreases
- the density of alkali metals generally increase
- reactivity increases
> the size of the atom increases, making it easier to lose valence electrons
what are the chemical properties of alkali metals?
- they are highly reactive metals
> stored in oil to prevent it from reacting with air and water - alkali metals react with cold water to form an alkali and hydrogen gas
> eg. lithium + water > lithium hydroxide + H2 - they are powerful reducing agents
- alkali metals form ionic compounds
what do alkalis react with, are, and what do they form?
- alkalis react with cold water to form alkali and hydrogen gas
- alkalis are powerful reducing agents
- alkali metals form ionic compounds
what are halogens and what are their physical properties?
- halogens are non-metals that exist as diatomic covalent molecules
> they have low melting and boiling points
> they are coloured
eg. chlorine: greenish-yellow gas
bromine: reddish-brown liquid
iodine: purplish-black solid
how do the physical properties of halogens change going down the group?
- their melting and boiling points generally increase
- the colours of the halogens becomes darker
- reactivity decreases
what are the chemical properties of halogens?
- halogens are reactive non metals
- they are in group VII
> have 7 electrons and only needs to gain one more for a stable electronic configuration of a noble gas - halogens reacts with most metals to form halides
what reactions do halogens
undergo and what type of agents are they?
- halogens undergo displacement reactions with halide solution
> DISPLACEMENT REACTIONS: a reaction in which one element takes the place of another in a compound
> a more reactive halogen with displace a less reactive halogen from its halide solution - halogens are powerful oxidising agents
- during chemical reactions, atoms of halogens readily gain electrons to form halide ions with a charge of -1
what is the order of reactivity of halogens?
- the reactivity of halogens decreases down the group
> the size of the atom increases down the group making it more difficult for the nucleus to attract one more electron
what are the properties of noble gases?
-noble gases are non metals
> are monoatomic
> colourless gases at room temperature
> have low melting and boiling points
> are insoluble in water
>are unreactive
why are noble gases unreactive?
- they have fully filled electron shells
> do not need to lose, gain or share electrons
> they rarely react to form compounds
