Question

1. who proposed the planetary model of the atom?

a. schrodinger
b. heisenberg
c. bohr
d. rutherford

1. the relationship between frequency and energy

a. can be described as direct.
b. can be described as inverse.
c. has no relationship.
d. can not be determined.

1. students in chemistry lab have been given the assignment to identify an unknown

compound using the flame test. the compound they are testing is a white crystal that emits
a greenish - light when placed in the flame. the unknown compound most likely contains _

element	flame color
copper	green
lead	blue
lithium	pink
sodium	orange
strontium	deep red

a. lead
c. strontium
b. barium
d. sodium

how many valence electrons does magnesium (atomic number 12) have?
a. 12
c. 6
b. 2
d. 24

the following sub - levels do the orbitals above represent?
c. d
d. f

Explanation:

1. Question about the unknown compound in flame - test

The problem mentions a white - crystal compound emitting a greenish light in a flame test. Referring to the provided flame - color chart, barium emits a yellow - green to green light.

Magnesium has an atomic number of 12. Its electron configuration is 1s²2s²2p⁶3s². The electrons in the outermost shell (3s²) are the valence electrons, and there are 2 of them.

The shape of the orbitals shown is that of a p - orbital. The p - sublevel has three orbitals oriented along the x, y, and z axes.

Answer:

b. Barium

2. Question about the number of valence electrons of magnesium