There are 29 electrons. Therefore, its electronic configuration is- (2,8,18,1)
(1) The outermost shell is the N shell with 1 electron
(2) The valency is 1 (as valence/outer electron is 1)
(3) Atomic no.= no. of protons= no. of electrons= 29
(4) This is certainly a metal (Copper) as the range of electrons is between 1-3 (1 here), so its valency is simply the no. of valence electrons in it, i.e. 1+)
If there are 1,2 or 3 electrons in the outermost shell, then the valency is the no. of outermost electrons
If there are 5,6,7 electrons, the valency can be obtained by subtracting the no from 8 , eg: if there are 6 electrons in the outermost shell, then valency=8-6=2
If there are already 8 electrons in the outermost shell, then valency is 0, that is those elements don't react, eg= Helium, argon
If there are 4 electrons, valency is 4 (8-4=4), so the elements start forming bonds.
Other elements either gain (valency 1,2,3) or lose electrons (valency 5,6,7).