Given: Wavelength λ = 410 nm convert to Meters m = 4.10 x 10⁻⁷ m
Speed of light c = 3 x 10⁸ m/s
Required: Frequency f = ?
Formula: c = λf
f = c/λ
f = 3 x 10⁸ m/s/4.10 x 10⁻⁷ m
f = 7.32 x 10¹⁴/s or 732 Thz (Terahertz)
Answer: True
Explanation:
Atomic number is defined as the number of protons or the number of electrons that are present in an electrically neutral atom.
Atomic number = Number of protons = number of electrons = 2
Electronic configuration represents the total number of electrons that a neutral element contains. We add all the superscripts to know the number of electrons in an atom.
The electronic configuration will be 
As its duplet is already complete and it has noble gas configuration , it is stable with 2 valence electrons.