The two elements 11X and 19Y are in the same group because they have the same
valence electrons
ionization energy
number of shell
atomic size
Correct answer is A
No explanation has been provided for this answer.
Hydrogen bonds are formed between molecules containing a hydrogen atom bonded to a
strongly electronegative atom
non-polar species
diatomic element
complex ion
Correct answer is A
No explanation has been provided for this answer.
linear
planar
pyramidal
tetrahedral
Correct answer is D
No explanation has been provided for this answer.
Which of the following substances is mainly responsible for the depletion of the ozone layer?
Oxgyen
Chlorofluorocarbon
Carbon (ll) oxide
Nitrogen (ll) oxide
Correct answer is B
Ozone depletion occurs when chlorofluorocarbons (CFCs) and halons—gases formerly found in aerosol spray cans and refrigerants—are released into the atmosphere
Cu and Sn
Cu and Zn
Cu and Mg
Cu and Pb
Correct answer is B
Brass is an alloy made from copper and zinc. Unlike pure metals, most alloys do not have a single melting point, but a melting range in which the material is a mixture of solid and liquid phases.