If an element, x, can form an oxide that has theformula x2o3, then element x would most likely be located on the periodic table in the same group as
(1) ba (3) in
(2) cd (4) na

(3) In

Explanation: As the given compound is , it can be said that X has a valency of 3.

1)Barium (Ba): Atomic no: 56: : In order to complete its octet, it needs to donate 2 electrons, and thus the valency is 2.

2) Cadmium (Cd) : Atomic no: 48: : In order to complete its octet, it needs to donate 2 electrons, and thus the valency is 2.

3) Indium (In): Atomic no: 49: : In order to complete its octet, it needs to donate 3 electrons, and thus the valency is 3.

4) Sodium (Na): Atomic no: 11: : In order to complete its octet, it needs to donate 1 electron, and thus the valency is 1.

So the given element could only belong to the group containing Indium (In) as all the elements in the same group exhibit similar valency.

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.