Question

type the symbol of each element that is described below: the lightest transition metal, the heaviest alkali metal, the third halogen element, the fourth noble gas element

Explanation:

1. Noble Gases: The noble - gas elements are in Group 18 of the periodic table. The first few noble gases are helium (He), neon (Ne), argon (Ar), krypton (Kr). The fourth noble gas is krypton with symbol Kr.
2. Halogens: The halogen elements are in Group 17 of the periodic table. The halogens are fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At). The third halogen is bromine with symbol Br.
3. Alkali Metals: The alkali - metal elements are in Group 1 of the periodic table. They include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr). The heaviest alkali metal is francium with symbol Fr.
4. Transition Metals: Transition metals are in the d - block of the periodic table. The lightest transition metal is scandium with symbol Sc.

Answer:

Kr
Br
Fr
Sc