Answer:
In first shell 2 electrons are present and 7 electrons are present in last shell
Explanation:
1. A. All the elements in the column have similar chemical properties.
2. Substances on the periodic table cannot be broken down into other substances and are therefore elements.
2 shells because if you do the electronic configuration:
2,7 which adds up to 9
7 stands for the group it in and it also stands for how many electrons are in the outer shell.
the amount of spaces stands for which period its in therefore it in period 2
I think its A. it cant be C or D b/c we are measuring the distance between Earth and Saturn, not the speed.