Name :
(a) three elements that have a single electron in their outermost shells.
(b) two elements that have two electrons in their outermost shells.
(c) three elements with filled outermost shells.

AcademicChemistryNCERTClass 10

(a) The three elements that have a single electron in their outermost shells are-
Lithium : Atomic number – 3(2, 1);
Sodium : Atomic number – 11(2, 8, 1);
Potassium : Atomic number – 19(2, 8, 8, 1).

(b) The two elements that have two electrons in their outermost shells are
Beryllium : Atomic number – 4(2, 2);
Calcium : Atomic number – 20(2, 8, 8, 2)

(c) Three elements with filled outermost shells are-
Helium : Atomic number – 2(2);
Neon : Atomic number – 10(2, 8);
Argon : Atomic number – 18(2, 8, 8).
raja
Updated on 10-Oct-2022 13:19:15

Advertisements