Journal Entry Journal Entry

Describe what you know Describe what you know about how electrons are about how electrons are arranged inside atoms.arranged inside atoms.

Keep writing until I ask you to Keep writing until I ask you to stop.stop.

Atomic StructureAtomic Structure

Drawing Atomic ModelsDrawing Atomic Models

Step 1Step 1

Re-number the groups Re-number the groups (columns) from 1 to 8, ignoring (columns) from 1 to 8, ignoring transition metals.transition metals.

Step 2Step 2

Find the number of protons Find the number of protons (from the atomic number) (from the atomic number)

Bismuth:Bismuth: 8383 Draw those into the nucleus.Draw those into the nucleus.

83 p+

Step 3Step 3

Round the average atomic mass to Round the average atomic mass to the nearest whole number and use the nearest whole number and use that as the mass number. that as the mass number.

A= 209A= 209 Subtract the atomic number from Subtract the atomic number from

it to get the number of neutrons. it to get the number of neutrons. #n = 126#n = 126

Draw those into the nucleus.Draw those into the nucleus.83 p+

126 n

Step 4Step 4

Look at the period number of Look at the period number of the row that the element is in. the row that the element is in. It tells you how many energy It tells you how many energy levels there are.levels there are.

Period # = 6Period # = 6 Draw that number of rings Draw that number of rings

around the nucleus.around the nucleus.

83 p+

126 nenergy levels: 1st 2nd 3rd 4th 5th 6th

Step 5Step 5

Look at the new group number Look at the new group number to tell how many electrons are to tell how many electrons are in the outermost energy level. in the outermost energy level.

Group # = 5Group # = 5 Fill in the number of electrons Fill in the number of electrons

in that outer level.in that outer level.

83 p+

126 nenergy levels: 1st 2nd 3rd 4th 5th 6th

5e-

Step 6Step 6

Starting in the 1st energy Starting in the 1st energy level, fill in the maximum level, fill in the maximum number of electrons in the 1number of electrons in the 1stst, , 22ndnd, and 3, and 3rdrd until you reach the until you reach the outermost. outermost.

1st = 2e-1st = 2e- 2nd = 8e-2nd = 8e- 3rd = 18e-3rd = 18e-

1st1st 22

2nd2nd 88

3rd3rd 1818

≥ ≥ 44thth 3232

83 p+

126 nenergy levels: 1st 2nd 3rd 4th 5th 6th

5e-2e- 8e- 18e-

Step 7Step 7

Find the number of electrons Find the number of electrons needed to finish the diagram and needed to finish the diagram and add those into the 4th-6th energy add those into the 4th-6th energy levels using 8, 18 and 32 electrons levels using 8, 18 and 32 electrons only.only.

Find the combination that adds Find the combination that adds electrons to all levels left and still electrons to all levels left and still adds up to the correct number total. adds up to the correct number total.

The inner level(s) should always The inner level(s) should always have more than the outer. have more than the outer.

Step 7Step 7 already added to diagramalready added to diagram

(2 + 8 + 18) + 5 = 33e-(2 + 8 + 18) + 5 = 33e- Need to add to diagramNeed to add to diagram

83 – 33 = 50 e- in 4th and 5th 83 – 33 = 50 e- in 4th and 5th 18 + 32 = 50 18 + 32 = 50 32 must be in 4th and 18 must be in 5th.32 must be in 4th and 18 must be in 5th.

83 p+

126 nenergy levels: 1st 2nd 3rd 4th 5th 6th

5e-2e- 8e- 18e-

32e-

18e-