Topic 4B Group 7 Flashcards
What is the trend in melting temperatures down group 7?
increases down the group
Why do the melting temperatures of group 7 increase down the group?
there is an increase in the number of electrons so the strength of london forces increases
What is sublimation?
the transition of a substance directly from the solid phase to the gas phase without passing through the intermediate liquid phase
What 3 factors does electronegativity depend on?
- nuclear charge- the bigger the nuclear charge, the higher the electronegativity
- distance between the nucleus and bonding pair of electrons, the shorter the distance, the higher the electronegativity
- the shielding effect of electrons in inner energy levels, the fewer energy levels, the higher the electronegativity
What is the trend of electronegativity down group 7?
decreases down the group (fluorine is the most electronegative)
What is the trend of reactivity down group 7?
decreases down the group
Why does the reactivity of group 7 decrease down the group?
- halogens tend to react by gaining an electron to their p-shell, they’re oxidising agents
- the atoms become larger as you go down the group, and the outer e- is further from the nucleus so less attraction to the positive nucleus
- outer e- is more shielded by inner shells as you go down the group
- this means that it is harder for the atom to attract electrons so reactivity decreases
What state is fluorine at room temperature?
gas
What is the state of chlorine at room temperature?
gas
What state is bromine at room temperature?
liquid
What state is iodine at room temperature?
solid
What colour is chlorine in water?
pale yellow-green
What colour is bromine in water?
yellow/orange
What colour is bromine in cyclohexane?
darker orange/red
What colour is iodine in water?
brown
