Frequency = speed of light
---------------------------
wavelength
= 3 x 10^8
------------------------
344 x 10^-9
= 8.72 x 10^14 Hz.
Hope this helps!
1st one is E
2nd one is also E
Answer:

Explanation:
Here in Calcium Chloride ionic bond is present in between calcium and chlorine atoms. As we know according to Octet rule calcium have two excess atoms and for matching nearest noble gas electronic configuration. It donate two electrons to gain more stability and form
, while chlorine is deficient from one electron to meet nearest noble gas electronic configuration therefore two chlorine atoms accept excess electron from calcium individually and form two
ions.

Hence aqueous solution of calcium chloride breaks the ionic bond pairing in one
and two
ions: 
When a monovalent cation X binds to a divalent anion Y, a compound with the formula
would be formed.
A monovalent cation is an atom that has lost an electron. Hence, such cation has a single positive charge. A monovalent cation X will, thus, be 
A divalent anion is an atom that has gained two electrons. Such anion has 2 negative charge. Thus, divalent Y would be 
Since Y is a divalent anion, it requires 2 electrons in order to successfully bind with another charged atom, a cation to be specific. Thus, two of
would be required to successfully bind 
+
+
---->
More on the chemical formula can be found here: brainly.com/question/16741890