Answer:4
Explanation:
As shown in the image attached, a face-centred cubic structure has 8 atoms at the corners and 6 face center atoms.
Each corner atom contributes to eight cell, so per unit cell 1/8 ×8 =1atom
Face center atoms contributes to two unit cells 1/2 × 6=3atoms
Total atoms =3+1=4atoms
Therefore the atoms in Al FCC per unit cell is 4
Fluorine 20 (F - Atomic number 9 and atomic mass 20). Firstly we need to know what is beta decay. Beta decay occurs when one neutron changes into a proton and an electron therefore the atomic mass will remain the same as even though we loose a neutron it is replaced by a proton, the atomic number is always raised by 1 when one beta decay occurs. The produced electron is shot out of the nucleus at an incredible speed. This speedy electron we call a beta particle.
Ok now the reaction.
20 20 0
F -> Ne + e
9 10 -1
Remember the atomic number determines the nature of the element ( i.e what elemnt it is).
Hope this helps :).
They use information from other things that relate to that topic and then use that to do their research
