Wavelength is the distance between crests of a wave. Wavelength can be calculated by the speed of light divided by frequency
Answer:
I think that the statement is relative to speed because it is saying km per second.
Explanation:
Y has 13 protons and we know that Aluminium (Al) too has 13 protons.
So , element Y = Aluminium
• In an element , no. of protons = no. of electrons. So , Y has 13 electrons.
• Mass no. of Y (Aluminium) = 27.
• Also we know that ,
Mass number = no. of protons + no. of neutrons
So,
No. of neutrons = 27 - 13 = 14
• Valence electrons are the electrons which are present in the outermost shell of an element.
Electronic Configuration of Y = 2,8,3
So, Y has 3 valence electrons.
• We know that Y is Aluminium & Aluminium is a metal. So , Y is a metal.
• Valency of Y = +3
