Explain why group 1 elements tend to form 1+ ions and group 7 elements tend to form 1- ions.

a) the number of electrons of the ions will be even numbers

b) the electron configuration of the ions will match that of a halogen

c) the electron configuration of the ions will match that of a noble gas

d) the number of electrons of the ions will be odd numbers

c) The electron configuration of the ions will match that of a noble gas  

Explanation:

The electron configuration of a noble gas is gives it the lowest energy.

a) and d) are wrong. The odd or even number of electrons don't necessarily make an ion more stable.

b) is wrong. The ions will not have the electron configuration of a halogen.

atomic number of carbon is 6

electronic configuration of carbon is 1s²2s²2p²

orbital diagram of carbon is as shown here in the image.

- decrease the number of plants and animals living in the water.