Answer:
Group 1 (or IA)
Explanation:
If element X is a halogen, then it belongs to the group 17 (or VIIA, under a different notation).
For each extra unit of atomic number, the group number increases by 1. That means that the X+1 element would belong to the group 18 (or VIIIA). <em>The X+2 element would thus belong in the group 1 </em>(or IA) one period higher (higher as in numeric value, not as in position in the periodic table).
<span>Electronegativity is the property of an element that measures the
ability of it to attract and form electron bonds. The trend in the periodic
table in terms of electronegativity decreases from right to left and from top
to bottom. In the case of period 4, the element with the highest electronegativity
is bromine. </span>
Answer:

Explanation:
Hello there!
In this case, since the thermodynamic definition of the Gibbs free energy for a change process is:

It is possible to plug in the given H, T and S with consistent units, to obtain the correct G as shown below:

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