Inorganic chemistry Flashcards
(23 cards)
Why is group 1 called the alkali metals
Form alkaline solutions when they react with water
What is a family of elements?
A group of elements that reacts in the same way
What happens when a group 1 metal is reacted with water
Vigorous
Metal hydroxide solution (alkaline)
Hydrogen produced (effervescence)
What is the word equation for the reaction of Group 1 metals with water?
Group 1 metal (s) + water (l) → metal hydroxide (aq) + hydrogen (g)
What is produced when lithium reacts with oxygen?
lithium oxide (Li₂O)
What is produced when sodium reacts with oxygen?
sodium oxide (Na₂O) or sodium peroxide (Na₂O₂)
What is produced when potassium reacts with oxygen?
potassium peroxide (K₂O₂) or potassium superoxide (KO₂)
Why do group 1 elements become more reactive as you go down the group?
The valence electron is further from the nucleus so it requires less energy to be lost
What are the physical properties of alkali metals
Soft
Relatively low melting points
Low densities (Li, Na, K float on water)
What does the reaction of lithium and water look like
Steady Effervescence
Slowly shrinks until it disappears
Floats and moves on water
What does the reaction of sodium and water look like
Rapid Effervescence
Melts to form a ball
Quickly becomes smaller until disappears
Floats and moves on water
What does the reaction of potassium and water look like
Rapid Effervescence
Quickly melts to form a ball
Burns violently with lilac flame
Disappears quickly
Floats and moves on water
What are the halogens
Elements in group 7
What occurs as you go down group 7 (physical)
Darker colour
Higher boiling point
What does chlorine look like at RTP
Pale green gas
What does bromine look like at RTP
Brown liquid
What does iodine look like at RTP
Purple-black solid
Why do the melting/boiling points of halogens increase going down the group?
Molecules become larger
Intermolecular forces become stronger
More energy is needed to overcome these forces
Why does reactivity decrease as you go down group 7?
Atomic size increases, making it harder for the halogens to gain electrons (they are further away from the nucleus)
What occurs when halogens react with metals?
Salts are formed
Metal halides
What is a halide?
A compound formed when a halogen reacts with another element
How do displacement reactions involving halogens/halides provide evidence for the trend in reactivity in group 7?
In displacement reactions, a more reactive halogen can displace a less reactive halogen from a compound, but not the other way round.
