C4.1 - predicting chemical reactions Flashcards
what is another name for Group 1 elements? (and why)
alkali metals, because they react with water to form alkaline solutions
state 4 properties of group 1 elements
- solid at room temperature
- can be cut with a knife (soft)
- shiny when freshly cut
- good conductor of electricity
how is softness affected as you go down the group 1 elements?
increases
what is the trend of density in group 1 elements?
increases (while going down list)
what is the trend for melting points of Group 1 elements?
decreases
how does reactivity change as you go down the Group 1 elements?
increases
how does lithium react with water?
fizzes steadily then slowly disappears
how does sodium react with water?
- melts to form a silver ball
- fizzes vigorously
- quickly disappears
how does potassium react with water?
- ignites immediately
- lilac flame
- quickly disappears
state the word equation of the reaction between Group 1 elements and water
metal + water -> metal hydroxide + hydrogen
give the balanced chemical formula (with state symbols) of when sodium reacts with water
2Na (s) + 2H20 (l) -> 2NaOH (aq) + H2 (g)
explain the trend of reactivity in Group 1 elements
- reactivity increases
- atoms become larger, and so harder for positive nucleus to attract outer electron (so easier to lose, and therefore react)
- outer electron’s distance from nucleus increases
- shielding (other electrons get in the way)
are halogens:
- nonmetals/metals
- brittle/solid
- conduct elecricity well/or not
- exist as mono-atomic/diatomic
- strong intermolecular forces/weak
- nonmetals
- brittle (solid)
- poor conductors of electricity
- exist as diatomic molecules
- weak im forces
describe fluorine at room temperature
pale yellow gas
describe chlorine at room temperature
green gas
describe bromine at room temperature
orange-brown liquid (vaporises easily)
describe iodine at room temperature
grey-back solid (sublimes to purple gas)
trend of density of group 7 elements?
increases
trend of melting/boiling points of Group 7 elements?
increases
what is another name for group 7 elements?
halogens
trend of reactivity of halogen elements?
decreases
do group 7 elements react with group 1 elements?
yes, vigorously
how do you explain the trend in reactivity of group 7 elements?
- decreases
- atoms become larger, and so harder for positive nucleus to attract other electrons electron (so harder to gain, and therefore react)
- outer electron’s distance from nucleus increases (so harder to gain electrons)
- shielding (other electrons get in the way) - amplified effect
what determines how reactive an element is?
how easily it loses/gains electrons
what is a halide?
a compound containing a group 7 element with one other element (hydrogen/metal)
how do you determine whether a halogen would displace another halide?
whether it is more reactive or not (or higher on the periodic table)
would chlorine displace bromine from bromides?
yes
where are the noble gases?
Group 0 (IUPAC group 18)
why are noble gases unreactive?
because they have full outer shells (little tendency to lose or gain electrons)
state features of noble gases
- conduct electricity
- odorless
- mono-atomic
- gases at room temperature
trend of boiling point of noble gases? (and why)
increases (atoms get larger, attractive forces become stronger) - GENERALLY VERY LOW
trend of density of noble gases (why)?
increases, larger atoms take up more space in set volume
GENERALLY VERY LOW - in gas state
state 4 properties of transition metals
- shiny (when freshly cut)
- good conductor of electricity
- strong
- malleable
how do transition metals compare to Group 1 metals (alkali metals)
- stronger + harder
- higher density
- higher melting point
are the transition metals reactive?
not really, react very slowly (if at all)
what do gold, platinum and iridium have in common?
do not react with water or oxygen at all
are alkali metals coloured in ionic compounds?
(no) colourless
are transition metals coloured in ionic compounds?
(yes) coloured
are transition metals good catalysts?
yes
What’s used for catalytic converters
catalytic converters
convert harmful gases in vehicle exhaust fumes into less harmful ones
platinum, rhodium and palladium
what is necessary for a metal fo react with water or a dilute acid? (reactivity)
for it to be more reactive than hydrogen
what is produced when a metal reacts with water?
metal hydroxide + hydrogen
what is produced when a metal reacts with a dilute acid?
salt (ie. sodium chloride) + hydrogen
how do you put metals into order of reactivity?
- place metal in water/dilute acid
- compared amount of bubbles/hydrogen produced
how would reactive non-metals react?
form covalent bonds with each other
