Which of the following substances does not have van der Waals' forces?
Copper
Graphite
Neon
Iodine crystals
Correct answer is A
No explanation has been provided for this answer.
Which of the following metals has the strongest metallic bond?
\(_{13}Al\)
\(_{19}K\)
\(_{12}Mg\)
\(_{11}Na\)
Correct answer is A
Aluminium has the highest magnitude of charge of +3, hence it will form a stronger metallic bond.
Na, Al, P, Cl
Cl, P, Al, Na
Na, P, Cl, Al
Al, Na, P, Cl
Correct answer is B
As you move across a period, first ionization energy increases.
The oxidation number of nitrogen in \(Pb(NO_{3})_{2}\) is
+2
+3
+4
+5
Correct answer is D
\(Pb(NO_{3})_{2}\) = \(+2 +2N + (-2\times 6) = 0\)
= \(2N = 10\)
⇒ \(N = +5\)
The reason for the decrease in the atomic size of elements across a period is that
nuclear charge increases while the outermost electrons are drawn closer to the nucleus
nuclear charge decreases while the outermost electrons are drawn closer to the nucleus
valence electrons increase across the period while the valence shell remains constant
nuclear charge decreases while the distance of the valence shell from the nucleus is increasing
Correct answer is A
This is caused by the increase in the number of protons and electrons across a period.