In the coordination
compound[cr(nh3)(en)2cl]br2,
thecoordination number (c. n.) and oxidation number (o. n.) of the
metalatom are, respectively,
a. c. n. = 6; o. n. = +4.
b. c. n. = 6; o. n. = +3.
c. c. n. = 5; o. n. = +2.
d. c. n. = 4; o. n. = +2.
e. c. n. = 4; o. n. = +3.

the correct option is A (C.N. = 6; O.N. = +4.)

Explanation:In the coordination

compound[Cr(NH3)(en)2Cl]Br2,

the coordination number (C.N.) and oxidation number (O.N.) of the

metal atom are 6 and +4 respectively.

it is to be noted that an alpha particle is an helium nucleus. so it contains 2 protons 2 neutrons and has a mass number of 4. when alpha decay particles are ejected from the nucleus it gets transformed into an atom which has atomic number less than 2 and a mass number less than 4.

an equation that could represent alpha decay is radium 226 decay of alpha particle forms radon 222.

→

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).