Question

an element belongs to group 18 and second period. identify the element and write its valency and number of Valence electrons.
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Answer 1

Answer:

Element: Neon

Valency: 0

Valence electron: 8

Explanation:

Valency is zero because it's octate is complete which henceforth makes it an inert gas.

Valence electron is eight because it's outermost shell contains 8 electrons

Answer 2

x²+7x+10=0

x²+2x+5x+10=0

x(x+2)+5(x+2)=0

(x+2)(x+5) = 0

x+2 = 0 ; x = -2

x+5 = 0 ; x = -5

Relationship between the zeroes and coefficients :-

Sum of zeroes = -2+(-5) = -2-5

= -7/1 = -x coefficient /x² coefficient

Product of zeroes = (-2)(-5)

= 10/1 = constant/x² coefficient