Elements like calcium located toard the top of a group have a high attraction for the valance electrons because they have

small atomic radius

Explanation:

Atoms on the top of a group are those with the smallest atomic number of the group they are in. As you go down the group in the periodic table, the atomic radius increases with the presence of additional shells owing to the increase in atomic number (hence electrons, and hence need for more shells to accommodate them). The smaller the atomic radius, the closer the valence electrons are to the nucleus, consequently the force of attraction on the electrons from the positively charged nucleus is stronger. The stronger the pull of the nucleus on the valence electrons, the smaller the radius becomes.

Hope this helps!

For cyclohexane compounds drawn in a chair conformation:   -axial bonds are vertical  -equatorial bonds are parallel to two bonds within the ring.  thus, as i assume the chair conformation is drawn:   -the x group is in an axial position, as are the five other vertical bonds.  -three axial bonds are on the top face of the ring  -the other three axial bonds are on the bottom face  the position of the second substituent on each ring carbon is equatorial.  gauche groups must be on an adjacent carbon such as carbon 6 and carbon 2, and also gauche groups are rotated by 60 degrees relative to each other.  drawing the newman projections for c1–c2 and c1–c6 aids in visualizing the groups that are gauche to the y group on c1.  click this link and watch some academic videos that may you more understand the topic