While looking at xenon (xe) on the periodic table, a student needs to find an element with a smaller atomic mass in the
same group where should the student look?
directly up
directly down
directly to the left
directly to the right

To find an element with a smaller atomic mass in the same group, one has to look directly up in the same group.

Option a

Explanation:

In the "modern periodic table", when you move down in the same group, the atomic number of the atom increases. The definition of relative atomic masses states that it is the weighted average of the isotopic masses, where the number of protons and the number of neutrons sums up to give the isotopic mass.

While going down the group, we are adding up the protons. And, hence increasing the "number of protons" eventually increases the "atomic mass of an atom". Therefore, to find the light-weighted element in the same group, one should look directly up.  

directly up

Explanation:

trust me

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-

i'm pretty sure it is letter c.) car