ANSWER
2 valence electrons
STEP-BY-STEP EXPLANATION:
The electronic configuration is given below as
Looking at the configuration, you will see that the last energy carries 2 electrons
Hence, the valence electrons are 2
T = 20 % : 20 / 100 = 0.2
m1 = solute
m2 = Solvent
T = m1 / m1 + m2
0.2 = 500 g / 500 g + m2
0.2 * ( 500 + m2 ) = 500
0.2 * 500 + 0.2 m2 = 500
100 + 0.2 m2 = 500
0.2 m2 = 500 - 100
0.2 m2 = 400
m2 = 400 / 0.2
m2 = 2000 g of water
hope this helps!
Answer : Option A) Atomic number of Arsenic is 33.
Explanation : Arsenic contains same number of protons in its atomic nucleus. In arsenic there are 33 protons found in the atomic nucleus. Hence, the atomic number will be 33. It has 5 valence electrons in its outermost shell, which is also called as valence shell. So, its valency becomes 5.
Radon is a naturally occurring radioactive gas. It comes from radioactive decay of uranium.
It is usually found in igneous rock and soil, but in some cases, well water can also be a source of radon.
Answer:
1.915e23 Atoms
Explanation:
There are 6.02214076e23 is the mass of a mol in amu. Since the amu of lead is 207.2, and there is 65.89 grams of it, you can find that it creates approximately 1.914 atoms.
