Nonmetals. The halogens
Answers are for parents and teachers.
1
Write the highest oxide and hydrogen compound formulas of Se (group VI).
SeO₃ and H₂Se
2
Complete the shells of an I atom: 2, 8, 18, 18, ? (53 electrons).
7
3
Write the electron transfer in Cl₂ + 2KI → 2KCl + I₂.
Cl₂⁰ + 2e⁻ → 2Cl⁻ (oxidizing agent); 2I⁻ – 2e⁻ → I₂⁰ (reducing agent).
4
Why does fluorine show only –1 in compounds?
It is the most electronegative element, pulls electrons from all atoms and gives none away.
5
Why must halogen vapours never be smelled?
They are poisonous and burn the airways; only a teacher works with them under ventilation.