5
3 items (or people) can line up in 6 different sequences. 6 items (or people) can line up in 720 different sequences.
two bonds and eight lone pairs
15C3 = 455
Eight.
35,280
5
3 items (or people) can line up in 6 different sequences. 6 items (or people) can line up in 720 different sequences.
Eight of them.
No.
two bonds and eight lone pairs
forty eight
The number of different ways that you can arrange 15 different items is given by the permutations of 15 things taken 15 at a time. That is 15 factorial, or 1,307,674,368,000.
15C3 = 455
There are 40,320 ways to arrange eight letters. In this case, around sixty of those ways will result in English words.
Eight has two factor pairs. Including their negative counterparts, that makes four pairs.
Eight pairs.