C4 Flashcards
what are group 1 elements known as?
Alkali metals
what 4 properties do group 1 elements have?
-low densities
-soft
-low melting and boiling points
-very reactive
why are alkali metals very reactive?
they have 1 electron in their outer shell, they easily from a full outer shell by losing it
does reactivity increase or decrease going down the group for alkali metals and why?
increases, the number of electron shells increases which means the attraction to the nucleus decreases
what is produced when an alkali metal reacts with water?
hydrogen gas + metal oxide
what do alkali metals form with non metals?
an ionic compound
what is produced when an alkali metal reacts with oxygen?
metal oxide
what are group 7 elements known as?
halogens
how many electrons do group 7 elements have in their outer shell?
7
what are the 2 properties of halogens?
-gases at room temp (only the top of group 7)
-solids at room temp (only the bottom of group 7)
do the melting and boiling points of halogens decrease or increase as you go down the group and why?
increase with increasing relative atomic mass. larger atoms have stronger intermolecular forces so more energy is needed to turn it into a gas.
does the reactivity in halogens increase or decrease as you go down the group and why?
decrease. halogens gain one electron for a full outer shell, it’s harder down the group because the number of shells decrease, it’s harder to gain an electron because it’s less attached to the positive nucleus.
what do halogens and non metals form?
molecular compounds, they share electrons (covalent bond)
what do halogens form when reacting with metals?
ionic compounds
what is group 0 also known as?
nobel gases
what are nobel gases at room temp?
colourless gases
does the melting point of noble gases increase or decrease as you go down the group?
increase with increasing relative atomic mass. larger atoms have stronger intermolecular forces between them, they need more energy to overcome the forces and turn into a gas.
how do you test for carbon dioxide?
bubble it through limewater, if carbon dioxide is present then the limewater will turn cloudy