Explanation:
A covalent bond is formed when an element shares its valence electron with another element. This bond is formed between two non metals.
An ionic bond is formed when an element completely transfers its valence electron to another element. The element which donates the electron is known as electropositive element and the element which accepts the electrons is known as electronegative element. This bond is formed between a metal and an non-metal.
Chlorine and potassium atoms form ionic bonds: Ionic bond is formed when there is complete transfer of electron from a highly electropositive metal to a highly electronegative non metal. Electronegativity difference = electronegativity of chlorine - electronegativity of potassium = 3-0.8 = 2.2
Carbon atoms form non-polar covalent bonds with nitrogen atoms : Non-polar covalent bond is defined as the bond which is formed when there is no difference of electronegativities between the atoms. Electronegativity difference = electronegativity of nitrogen - electronegativity of carbon= 3.0-2.5 = 0.5
Oxygen forms polar covalent bonds with phosphorus: A polar covalent bond is defined as the bond which is formed when there is a difference of electronegativities between the atoms. Electronegativity difference = electronegativity of oxygen - electronegativity of phosphorous = 3.5- 2.19 = 1.31
A chemical element is a substance that is made up of only one kind atom.
Wavelength of the light is 2.9 × 10⁻⁷ m.
<u>Explanation:</u>
Planck - Einstein equation shows the relationship between the energy of a photon and its frequency, and they are directly proportional to each other and it is given by the equation as E = hν,
where E is the energy of the photon
h is the Planck's constant = 6.626 × 10⁻³⁴ J s
ν is the frequency
From the above equation, we can find the frequency by rearranging the equation as,
ν = 
= 
Now the frequency and the wavelength are in inverse relationship with each other.
ν × λ = c
It can be rearranged to get λ as,
λ = c / ν
= 
So wavelength is 2.9 × 10⁻⁷ m.
Calcium fluoride.
Ca is metal, F is non-metal, so they form ionic bond.
Ca as metal can form only positive ion. Ca in the second group, so the charge of Ca ion is 2+. Ca²⁺
F is in the 17th group, so it has 7 electrons on the last level. It is non-metal, non-metal, so it has negative charge -(8-7)=-1. "8" because on the last level cannot be more than 8 electrons. F-ion is F¹⁻.
Ca²⁺ F¹⁻
Number of positive charges should be equal to number of negative charges,
Formula of calcium fluoride
CaF2.
2 atoms Fluorine bond with Calcium.
