The correct answer would be the last one.
As you move around there is a change in: electronegativies, ionisation energies, atomic radius etc. different amounts of these properties are going to effect how the element acts
<span>A covalent bond is a bond formed by atom sharing.
In water molecule, there are twice the number of hydrogen atoms than the oxygen atoms. Its structure is H-O-H. The electronegative difference between the H and O allows them to be polar because on side there is positive charge and on another side there is negative charge.</span>
C, potassium. Hope this helps.
