Why does the top period only have two elements?

Answer 1

Because there are only two elemets whose electrons fill up the first shell of electrons.

Hydrogen: 1 proton, 1 elecrton.

Helium: 2 protons, 2 neutrons, and 2 electrons.

The next on the table, lithium, has 3 electrons, going into the next shell of electrons. The maximum the first shell can hold is two, and helium fills it all, therefore being a stable element and not combining with anything. Hydrogen, on the other hand can combine with elements that have 1 less electron in their last shell. An example of this is oxygen with seven electrons in its last shell. Oxygen creates water with hydrogen.

Answer 2

Period 1 represents The first atomic shell, which has only one s orbital. The s orbital can hold a maximum of two electrons.

Therefore, you have the first element in Period1, hydrogen, which has 1 electron, and the second, helium, which has 2 electrons.

Answer 3

The first energy level can hold a maximum of two electrons. All but H and HE have more than two electrons. and becuase poo

Answer 4

as the first shell can accommodate maximum two electrons therefore first period has two elements.

Answer 5

eash shell /orbit had diffrent energy level so in the first shell the energy is n 1x1=n=1.; 1 1=2 if n =2 2x2x2=8

Answer 6

Only hydrogen and helium have only one electrons shell.