Name an element in the fifth period (row) of the periodic table with a complete outer shell.

The element in fifth period of the periodic table having complete outer shell is Xenon.

Explanation:

Elements are distributed in 7 periods and 18 groups. Groups are the vertical columns and periods are the horizontal rows.

Element having complete outer shells are present in Group 18 of the periodic table. These elements are known as noble gases.

Element present in Period 5 and Group 18 of the periodic table is Xenon.

The atomic number of Xenon is 54.

Hence, the element in fifth period of the periodic table having complete outer shell is Xenon.

"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"