The answer is 2 electrons.
The electron configuration of calcium is 2:8:8:2
Calcium has two electrons in its outermost shell. These are its valence electrons and are the ones used in bonding with other elements. Valence electrons of an atom are those electrons that are in its outer energy shell or that are available for bonding.
Calcium is a metal. When metals react with non-metals, electrons are transferred from the metal atoms to the non-metal atoms forming ions. The resulting compound is known as an ionic compound.
For example, when calcium metal reacts with chlorine gas, calcium gives up its two valence electrons and Chlorine accepts them resulting in a new substance called calcium chloride in which the two elements have ended up forming ionic bonds.
Answer:
Water has a higher boiling point because the hydrogen bonds that form water molecules are stronger than the Van der Waals interactions among methane molecules, therefor more energy must be provided in order to break the hydrogen bonds and allow the water molecules to escape the liquid state.
Explanation:
Answer:
Answer B) 4.2x10^17
Explanation:
To produce the reaction 3 using reaction 1 and 2 we need to invert the order of the first reaction the second in the same order, as it's shown:


____________________________

Due to the inversion of the first equation, the equilibrium constant of the new reaction is K1'=1/K1.=2.4x10^30
Finally, the new equilibrium constant K3 is the product of the previous constants:
K3=K1'*K2=4.2x10^17
Answer:
C) 295 kJ/mol (average of the values given)
Explanation:
We can use Hess' Law to calculate the energy of formation of the C-Cl bond:
C-C → 2C ΔH = -347 kJ/mol
Cl-Cl → 2Cl ΔH = -243 kJ/mol
_______________________
C + Cl → C-Cl ΔH = (-347/2)+(-243/2)
ΔH = -295 kJ/mol