The atomic number increases as you go left to right on the periodic table, the atomic number represents the number of protons in the nucleus, and an element has a neutral charge, so it will have to possess an equal number of electrons. So yes, as you move across a period left to right the number of electrons increase.
unless we are talking about the first period, in which it does increase as you go across. also i believe that they either grow closer to the nucleus as they go across. dont quote me but im pretty sure thats what happens
accross a period, core electrons remain the same, valence electrons increase. down a group, shielding is increased because there are more core electrons, and the elements dont get all the love they want from the nucleas, so it's easier to remove electrons.
ahaha wow i hate chemistry. i took that chem last semester, and already forget soooooooo much of it!