Which of the following best helps to explain why the atomic radius of K is greater than that of Br? A) The first ionization energy of K is higher than that of Br.
B) The valence electrons in K are in a higher principal energy level than those of Br.
C) In the ground state, an atom of K has fewer unpaired electrons than an atom of Br has.
D) The effective nuclear charge experienced by valence electrons is smaller for K than for Br.

c. orbital shape i hope this is correct

on passing the small ampere of electric current through the tube made of ar and hg of cfl generates uv rays which excites the fluorescent and thus emits the high radiation by consumption of just 5- 12 w in comparison to incandescent light which requires more power such as around 40 - 55 w to lighten.

moreover the life span of fluorescent or cfl is around 8000 h whereas the life span of incandescent is around 1200 h

hence, the building installed with incandescent lights bears more electricity bill.

a). in this case, dh> 0 and sd> 0. if t becomes larger, the term "-tds" will become more negative. at some point, it is possible that -dts will be more negative than the dh is positive, and the reaction will become spontaneous. this is probably the correct answer, but you should look at all of the other possibilities and make sure of that.