What do these compounds have in common?
h2o
cl2
nh3

a)
they are all ionic.
eliminate
b)
they are all covalent.
c)
they all are positively charged.
d)
they all are negatively charged.

2. the electron configuration of an element is 1s22s22p63s23p64s1. why is this a representative element?
a)
all orbitals are completely filled.
eliminate
b)
the outermost electron is a valence electron.
c)
the outermost electron is added to the p-orbital.
d)
the highest s-orbital or p-orbital is partially filled.

Evaluate this exponential expression,8. (2 + 3)2 – 42

The scheme below is from a series of reactions that are part of a synthesis of vitamin a. answer the following questions with reference to this scheme. (i) what is "reagent a"? (ii) draw a step-by-step mechanism which explains the formation of compound c from compound b (iii) which reagents would you use to form compound e from compounds c and d (reagents b and c)? for each reagent suggested above in (ii) explain the role of the reagent in the reaction to (iv) form compound e. you may wish to do this by drawing a mechanism. 1. addition of reagent a но reagent a 2. н, о" thо oh нон-с compound a. compound b. compound c .ch-оh 1. reagent b "сно 2. reagent c сh oh compound e. compound d.

What was bohr’s contribution to the planetary model