20 POINTS PLEASE ANSWER

What trend does the first ionization energy follow in the periodic table?

a it increases when going down a group

b it decreases when going across a family

c it decreases when gpoing down a group

d it stays the same within a family

PLEASE ANSWER I CANT FIGURE THIS ONE OUT

ITS C I GOT IT RIGHT NVM

c. It decreases when going down a group.  

Explanation:

Ionization energy is the energy needed to remove an electron from the neutral gaseous atom.

It is represented in kJ/mol.

As we move down the group the ionization energy decreases, since the outermost electrons are far away from the nucleus of an atom and so attains greater shielding effect. They encounter a weaker force of attraction to the +ve charge on the nucleus. And so, Ionization energy decreases from top to bottom in a group.

option c: 1605.1 kj

the balanced chemical reaction for combustion of methane is as follows:

here, enthalpy formation of is -74.7 kj/mol, 0 kj/mol, -393.5 kj/mol and -241.82 kj/mol respectively.

the heat released or can be calculated as follow:

putting the values,

thus, heat released by combustion of 1 mol of methane is 802.54 kj/mol. thus, for 2 mol, heat released will be:

therefore, heat released by the combustion of 2 mol of methane is 1605.1 kj.