Формула вещества 3-метилпентин-4

Ihave a big family.we are 7; my mother,my father, my sister,my brother,my grandmother , my grandfather and i.my father is a businessman.he works hard.my mother is a teacher.i love her very much.my grandfather works.he has his own business.he likes his work.he has a small dining room.my granmother is a houswife.she looks after the children.she is a very nice woman.my brother is a student.he studies at moscow theatrical university.my sister is a schoolgirl.she goes to school. she is in the eight form.she is pretty.and finally about me.i'm a schoolgirl.i 'm in the seventh form.i go to english couses.i want to go to gym.i'm planning to exesises.

На количество электронов на внешнем уровне указывает номер группы. Номер группы 5 – кол-во электронов на уровне 5

4 - H2O , SiO , CO2 / / / / /

На счёт 2 не уверена , но первое точно