Answer:
8.99×10^-7m
Explanation:
The wavelength can be calculated using the expression below
E=hcλ
Where E= energy= 2.21 x 10^-19 J.
C= speed of light= 3x10^8 m/s
h= planks constant= 6.626 × 10^-34 m2 kg / s
E=hcλ
λ= E/(hc)
Substitute for the values
λ=( 2.21 x 10^-19 )/(6.626 × 10^-34 × 3x10^8 )
= 8.99×10^-7m
The group is might be labeled as VIIB or VIIA.
The study of plants, plant life cycles, photosynthesis, plant parts, etc. is under botany (study of plants).
Potassium oxide has the antifluorite structure. The antifluorite structure have compounds with the stoichiometry X₂Y, where X is the cation and Y is the anion. In the antifluorite structure <span>positions of the </span>cations<span> and </span>anions<span> are reversed relative to their positions in calcium fluoride.</span>
Potassium ions coordinated to 4 oxide ions, <span>potassium ions are all in the tetrahedral holes.</span>
