Question

bohr model worksheet
for each element draw the inner electrons blue & the valence (outer) electrons red. the circles represent possible electron shells.
sodium (na) ____
aluminum (al) ____
carbon (c) ____
silicon (si) ____
oxygen (o) ____
chlorine (cl) ____
fluorine (f) ____
phosphorus (p) ____
lithium (li) ____

Explanation:

Step1: Recall electron - shell capacities

The first shell can hold 2 electrons, the second shell can hold 8 electrons, and the third shell can hold 8 electrons (for these small - atomic - number elements considered here).

Step2: Determine electron numbers for each element

• Sodium (Na) has 11 electrons. Inner electrons: 2 in the first shell and 8 in the second shell (blue). Valence electron: 1 in the third shell (red).
• Aluminum (Al) has 13 electrons. Inner electrons: 2 in the first shell and 8 in the second shell (blue). Valence electrons: 3 in the third shell (red).
• Carbon (C) has 6 electrons. Inner electrons: 2 in the first shell (blue). Valence electrons: 4 in the second shell (red).
• Silicon (Si) has 14 electrons. Inner electrons: 2 in the first shell and 8 in the second shell (blue). Valence electrons: 4 in the third shell (red).
• Oxygen (O) has 8 electrons. Inner electrons: 2 in the first shell (blue). Valence electrons: 6 in the second shell (red).
• Chlorine (Cl) has 17 electrons. Inner electrons: 2 in the first shell and 8 in the second shell (blue). Valence electrons: 7 in the third shell (red).
• Fluorine (F) has 9 electrons. Inner electrons: 2 in the first shell (blue). Valence electrons: 7 in the second shell (red).
• Phosphorus (P) has 15 electrons. Inner electrons: 2 in the first shell and 8 in the second shell (blue). Valence electrons: 5 in the third shell (red).
• Lithium (Li) has 3 electrons. Inner electrons: 2 in the first shell (blue). Valence electron: 1 in the second shell (red).

Answer:

• Sodium (Na): Inner electrons (blue): 2 in first shell, 8 in second shell; Valence electron (red): 1 in third shell.
• Aluminum (Al): Inner electrons (blue): 2 in first shell, 8 in second shell; Valence electrons (red): 3 in third shell.
• Carbon (C): Inner electrons (blue): 2 in first shell; Valence electrons (red): 4 in second shell.
• Silicon (Si): Inner electrons (blue): 2 in first shell, 8 in second shell; Valence electrons (red): 4 in third shell.
• Oxygen (O): Inner electrons (blue): 2 in first shell; Valence electrons (red): 6 in second shell.
• Chlorine (Cl): Inner electrons (blue): 2 in first shell, 8 in second shell; Valence electrons (red): 7 in third shell.
• Fluorine (F): Inner electrons (blue): 2 in first shell; Valence electrons (red): 7 in second shell.
• Phosphorus (P): Inner electrons (blue): 2 in first shell, 8 in second shell; Valence electrons (red): 5 in third shell.
• Lithium (Li): Inner electrons (blue): 2 in first shell; Valence electron (red): 1 in second shell.