Answer: All of these aswers would be correct
Explanation:
Tin, because it has five energy levels with four electrons in the fifth level
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Explanation:
Tin has an electronic configuration as
1s2,2s2,2p6,3s2,...........4d10, 5s2,5p2
They have four valence electrons in their outer shell
Among the four diagrams given Tin is least reactive because the atomic radius of tin is largest among all four options. Due to large atomic radius electronegativity decreases and hence Tin is the least reactive element among Neon, Chlorine, gallium and tin.
The electronegativity of an element is its tendency to complete its octet by attracting electrons towards itself. Also tin is at the lowest place in the periodic table among all the four mentioned elements, its ionization energy is also low hence less electronegative and least reactive.
A theory is a hypothesis that someone had but has not proven it.
A law is something that is proved.
Example: Sir Issac Newton had a theory on gravity he sat under a tree and then had a conclusion.
To signal hunger, the physiological need for food, the digestive tract sends messages to the hypothalamus by way of hormones and nerves.
