Question

pls tell me...pls pls
1.three elemwnts that have single electrons in their outer most shell.
2.two elements that have two elwctrons ib their outermost shell.
3.three elements that is filled with outermost shell.

Answer 1

1.All the Earth alkali metals have single electron in there outermost shell or valence shell. These are all metals which are present in the first group of modern periodic table. Examples are Hydrogen, Lithium,Sodium,Potassium, Rubidium,Cesium and Francium.
2.All Alkali metals have double electrons in their outermost shell or valence shell. These are found in the second group of modern periodic table. Examples are Beryllium, Magnesium, Calcium, Strontium, Barium and Radium.
3. All the Noble gases have valence shell or outermost shell filled. These are present in the 18th group of modern periodic table. Examples are Helium, Neon, Argon, Krypton, Xenon and Radon.

I hope this would have clear to you.

Answer 2

(a) Li, (2, 1), Na, (2, 8, 1) and K(2, 8, 8, 1)

(b) Be, (2, 2) and Mg (2, 8, 2)

(c) He, (2), Ne, (2, 8) and Ar (2, 8, 8)