Hi,

can you tell me what the valency of Aluminium and Selenium?

is this the question from q1a i got H+1 and -2

Is that what you thought

Answered above.

Sure! The valency of an element refers to its ability to form chemical bonds. To determine the valency of an element, we need to look at its electron configuration.

For Aluminium (Al), we can find its valency by looking at its electron configuration. Aluminium has an electron configuration of 1s^2 2s^2 2p^6 3s^2 3p^1. We can see that aluminium has three valence electrons in its outermost shell. Valence electrons are the electrons in the outermost shell of an atom. Since aluminium has three valence electrons, its valency is +3.

For Selenium (Se), it has an electron configuration of 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^4. From its electron configuration, we can see that selenium has six valence electrons in its outermost shell. Therefore, the valency of selenium is -2.

So, the valency of Aluminium is +3 and the valency of Selenium is -2.