Os This question is about elements from these families alkali metals, alkaline earth metals (Group II), transition denents, halogens, noble gases
*) is a soft, silvery metal that reacts violendy with water
b) is a gas at room temperature. It reacts violendy with other elements, without heating
c) is an unreactive was that sinks in air

* is a soft,silvery metal that reacts violently with water

is a soft silverymetal

Explanation:

that recats violendy with water

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."

the answer is 1260

you spend 7 hours in school for 1 school day with 5 school days in 1 school week with 36 school weeks in a school year.

7*5*36= 1260 it's all about multiplying