78 protons and 55 elections
55 protons and 78 neutrons
55 neutrons 78 electrons
78 protons and 55 neutrons
Correct answer is B
No explanation has been provided for this answer.
XY
YX
X2Y3
Y2X3
Correct answer is D
\(\frac{\text{Element X}}{1s^22s^21p^4}\)
Valency of X is 2
\(\frac{\text{Element Y}}{1s^22s^22p^63s^23P^1}\)
valency of Y is 3
There is an exchange of valency when a compound is being formed. Hence, we have Y\(_2\)X\(_3\)
electropositivity decreases from Li to Na to K
electronegativity decreases from Li to Na to K
the number of the electron shells increases from Li to Na to K
the elements are in the same period
Correct answer is C
No explanation has been provided for this answer.
737 mm Hg
763 mm Hg
777 mm Hg
783 mm Hg
Correct answer is A
No explanation has been provided for this answer.
25.0cm3
12.5 cm3
10.0 cm3
5.0cm3
Correct answer is B
No explanation has been provided for this answer.