Answer:
______is used in production of hard disk.
Explanation:
Answer:
-2
Explanation:
Calcium is the element of second group and forth period. The electronic configuration of Calcium is - 2, 8, 8, 2 or 
There are 2 valence electrons of Calcium.
Thus, calcium loses two electrons to sulfate ion and sulfate ion accepts these electrons to form ionic bond.
Calcium sulfate, 
is formed when 2 valence electrons of calcium are loosed and they are gained by sulfate ion.
Thus, the charge on the sulfate ion is -2.
Answer:
option D= Gold (I) nitride
Explanation:
The name of the given compound is gold(I) nitride.
Molar mass can be determine by following way:
molar mass Au3N = (molar mass of gold × 3) + (molar mass of nitrogen)
molar mass Au3N = (196.97 × 3 ) + ( 14 )
molar mass of Au3N = 590.91 g/mol + 14 g/mol
molar mass of Au3N = 604.91 g/mol
The nitrogen has valency of -3 so three Au(+1) will require while the valency of Au is (1+) one nitrogen will require to make the compound overall neutral.
Au3N
3(1+) + (-3) = 0
+3 - 3 = 0
0 = 0
The overall charge is 0, the compound will be neutral.
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 :).
