Selenium falls in the same column with oxygen therefore it has the same number of valence electrons with oxygen which is 6. It fills the 3d orbital but only 4s and 4p are counted. The electronic configuration is [Ar]3d^10 4s^2.
Answer:
Wavelength (λ) – The distance of one complete cycle in the wave. The distance between two consecutive crests and /or troughs. S.I. Unit: metre (m).
In other words:
Wavelength is the distance from crest to crest (or trough to trough).
A.electrons are shared between two different nuclei
Answer: D. A buildup of mostly methane gas, which is pontentially explosive.
Explanation:
Firedamp refers to a gas mixture, largely methane, that appear in underground coal mines. It is explosive at concentrations between 5 and 10% in the air.