Covalent bonds formed when two atoms share an electron, as opposed to an Ionic bond where one atom takes an electron(or two) from another atom.
Answer:

Explanation:
The work function of the sodium= 495.0 kJ/mol
It means that
1 mole of electrons can be removed by applying of 495.0 kJ of energy.
Also,
1 mole =
So,
electrons can be removed by applying of 495.0 kJ of energy.
1 electron can be removed by applying of
of energy.
Energy required =
Also,
1 kJ = 1000 J
So,
Energy required =
Also,
Where,
h is Plank's constant having value
c is the speed of light having value
So,
Also,
1 m = 10⁻⁹ nm
So,

Answer:
CaCl2
Explanation:
As temperature increases pressure also increases so when the temperature is at 25 degrees C CaCl2 is already soluable in 100g of h20
Answer:
2 M
Explanation:
mole weight of CaBr2 = 40 + 2 * 79.9 = 199.8 gm
20 gm is then 20/199.8 =.1 mole
.1 mole / .50 liter = 2 M
Electrical?
Hope this helps