Question

electron configuration

1. how many electrons can each level hold? 1st = __ 2nd = 3rd = __
2. what term is used for the electrons in the outermost shell or energy level? ____
3. scientists use two types of diagrams to show the electron configuration for atoms. follow your teacher’s directions to complete the diagrams.

sulfur
atomic # = 16
atomic mass = 32
protons =
neutrons =
electron =

bohr diagram
shows all electrons

lewis structure
shows valence electrons

1. calculate the missing information and then draw the bohr diagram and lewis structure for each element.

li
atomic # = 3
mass # = 7

of p = ____

of n = ____

of e = ____

ne
atomic # = 10
mass # = 20

of p = ____

of n = ____

of e = ____

mg
atomic # = 12
mass # = 24

of p = ____

of n = ____

of e = ____

cl
atomic # = 17
mass # = 35

of p = ____

of n = ____

of e = ____

he
atomic # = 2
mass # = 4

of p = ____

of n = ____

of e = ____

si
atomic # = 14
mass # = 28

of p = ____

of n = ____

of e = ____

1. answer the questions below based on the elements in question #15.

(1) which elements had a filled outermost shell? __ __
(2) which element would be most likely to lose electrons in a chemical bond? ____
(3) which element would be most likely to gain electrons in a chemical bond? ____
(4) which elements are not likely to bond with other elements? __ why? __

Explanation:

Step1: Solve Q12: Electron capacity per level

Recall electron level formula: $2n^2$
1st level ($n=1$): $2(1)^2 = 2$
2nd level ($n=2$): $2(2)^2 = 8$
3rd level ($n=3$): $2(3)^2 = 18$

Step2: Solve Q13: Define outer shell electrons

The term for outermost shell electrons is valence electrons.

Step3: Solve Q15: Calculate subatomic particles

Use rules:

• Protons ($P$) = Atomic Number
• Neutrons ($N$) = Mass Number - Atomic Number
• Electrons ($E$) = Atomic Number (neutral atoms)

Lithium (Li):

$P = 3$, $N = 7-3=4$, $E=3$

Neon (Ne):

$P=10$, $N=20-10=10$, $E=10$

Magnesium (Mg):

$P=12$, $N=24-12=12$, $E=12$

Chlorine (Cl):

$P=17$, $N=35-17=18$, $E=17$

Helium (He):

$P=2$, $N=4-2=2$, $E=2$

Silicon (Si):

$P=14$, $N=28-14=14$, $E=14$

Step4: Solve Q16: Chemical behavior questions

1. Filled outer shell: Noble gases (He, Ne)
2. Most likely to lose electrons: Group 1/2 metal (Li)
3. Most likely to gain electrons: Group 17 nonmetal (Cl)
4. Non-bonding elements: Noble gases (He, Ne), they have full valence shells.

Answer:

1. 1st = 2, 2nd = 8, 3rd = 18
2. Valence electrons

15.

• Li: # of P = 3, # of N = 4, # of E = 3
• Ne: # of P = 10, # of N = 10, # of E = 10
• Mg: # of P = 12, # of N = 12, # of E = 12
• Cl: # of P = 17, # of N = 18, # of E = 17
• He: # of P = 2, # of N = 2, # of E = 2
• Si: # of P = 14, # of N = 14, # of E = 14

16.
(1) He, Ne
(2) Li
(3) Cl
(4) He, Ne; They have a full, stable valence electron shell.

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Diagram Notes (for Q14 and Q15):

• Sulfur Bohr Diagram: 2 electrons in 1st shell, 8 in 2nd, 6 in 3rd
• Sulfur Lewis Structure: Symbol S with 6 dots around it
• Li Bohr Diagram: 2 electrons in 1st shell, 1 in 2nd; Lewis Structure: Li with 1 dot
• Ne Bohr Diagram: 2 electrons in 1st shell, 8 in 2nd; Lewis Structure: Ne with 8 dots
• Mg Bohr Diagram: 2 electrons in 1st shell, 8 in 2nd, 2 in 3rd; Lewis Structure: Mg with 2 dots
• Cl Bohr Diagram: 2 electrons in 1st shell, 8 in 2nd, 7 in 3rd; Lewis Structure: Cl with 7 dots
• He Bohr Diagram: 2 electrons in 1st shell; Lewis Structure: He with 2 dots
• Si Bohr Diagram: 2 electrons in 1st shell, 8 in 2nd, 4 in 3rd; Lewis Structure: Si with 4 dots