The initial two columns of the periodic table make the s-square, and the components in this square share practically speaking that they have a tendency to lose electrons to pick up soundness.
Explanation:
Atomic size gradually decreases from left to right across the periodic table because within a period of elements, all electrons are added to the same shell. However, at the same time, protons are being added to the nucleus, making it more positively charged. The effect of increasing proton number is greater than that of the increasing electron number. Therefore, there is a stronger nuclear attraction. This means that the nucleus attracts the electrons more strongly, pulling the atom's electron shells closer to the nucleus. As a result, the atomic diameter of the atom decreases.
The average weight of an atom of an element, formerly based on the
weight of one hydrogen atom taken as a unit or on 1/16 (0.0625) the
weight of an oxygen atom, but after 1961 based on 1/12 the weight of the
carbon-12 atom.
Answer : The de Broglie wavelength will be 
Solution :
The formula used for de Broglie wavelength is:
..........(1)
where,
= wavelength = ?
h = Planck's constant = 
m = mass = 1.2 g = 0.0012 kg
Conversion used : 1 kg = 1000 g
v = velocity = 150 m/s
Now put all the given values in equation 1, we get:
Therefore, the de Broglie wavelength will be
