Given that the electronic configuration of an element X is 1s2 2s2 2p6 3s2 3p4,it can be deduced that X: a. belongs to group VI in the periodic table
b. belongs to period 4 in the periodic table
c. contains 3 unpaired electrons in the ground state
d. has atomic number 27

Option A

Explanation:

The element X belongs to

=> Period 3 (Because it's valence shell is 3)

=> Group VI (Because electrons in the valence shell , 2+4 = 6)

these nuts

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"