<u>Answer:</u> The electronic configuration of gallium is written below and number of valence electrons is 3.
<u>Explanation:</u>
Electronic configuration is defined as the representation of electrons around the nucleus of an atom.
Number of electrons in an atom is determined by the atomic number of that atom.
Valence electrons are defined as the electrons present in the outermost shell of an atom.
We are given:
An element Gallium having atomic number as 31.
Number of electrons = 31
Electronic configuration of Gallium is: 
This element has 3 electrons in its outermost shell. So, the number of valence electrons is 3
Hence, the electronic configuration of gallium is written below and number of valence electrons is 3.
Yes its True. If we consider the electronegativity difference of Carbon and Bromine it is,
E.N of Bromine = 2.96
E.N of Carbon = 2.55
_________
E.N difference = 0.41
As the E.N difference is greater than 0.4 so this bond is slightly polar. And Bromine more electronegative than carbon will attract the electrons density towards itself making carbon partial positive, and itself partial negative.
Explanation:
The ionic strength of a solution, I, is defined as
I=1/2 Σ m_i z_i^2
Where m_i is the concentration of the ion, and z_i is the charge of the ion.
For 1 M NaCl solution, Ionic strength I = ½ (1*12 + 1*12) = 1.00;
For, 1 M (NH4)2SO4, concentration of [NH4] = 2 M and [SO4] = 1 M;
I = ½ (2*12 + 1*22) = 3.00;
so ionic strength of 1 M (NH4)2SO4 is different, therefore it is a serious error.
1: viewing any chemical reaction in a laboratory
2: dangerous to look at when it burns & used in photography, fireworks, and flares
3: the product