How many lone pair (s) of electrons is present in HF?
0
1
2
3
Correct answer is D
No explanation has been provided for this answer.
NH4- is formed from NH3 and H- by
covalent bonding
dative bonding
hydrogen bonding
ionic bonding
Correct answer is B
No explanation has been provided for this answer.
The relative atomic mass of chlorine is not a whole number because
it is the weighted average mass of all its various isotopes
it is the average mass of all the isotopes of the element
the element has strong oxidizing ability
the atom contains a higher number of neutrons than protons
Correct answer is B
Chlorine is a mixture of two isotopes with different abundances. Its relative atomic mass is the mean or average of the isotopic masses.
1718W
1817W
3517W
3518W
Correct answer is C
The superscript is the atomic mass = 35
(The mass number also called atomic mass number or nucleon number, is the total number of protons and neutrons)
The subscript is the atomic or proton number = 17
The number of electrons in a neutral atom is equal to the number of protons.
Which of the following transition metals is not attracted to external magnetic field?
Cu
Fe
Ti
Zn
Correct answer is A
The period 4 transition metals are scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), and zinc (Zn).
Diamagnetism results from the lack of unpaired electrons. Diamagnetic substances are substances that are repelled by magnetic fields.
The examples of diamagnetic materials are copper, gold, antimony, silver, lead and hydrogen.