Question

in 1943, niels bohr described the atom as a planetary system with electrons orbiting around the nucleus. bohrs model is incomplete, but it nonetheless is helpful in understanding why some atoms are very reactive and others are less so. directions: complete each of the following models using what you know about atoms. the first is completed for you as an example. atomic # 7 atomic mass 14 isotope name: nitrogen symbol n valence e# __ atomic # atomic mass 12 element: symbol c valence e# atomic # atomic mass 40 element: symbol valence e# atomic # atomic mass element: symbol h valence e# atomic # atomic mass 40 element: symbol valence e# atomic # atomic mass 11 element: symbol b valence e# atomic # atomic mass 27 element: symbol valence e# atomic # atomic mass 32 element: symbol valence e# atomic # atomic mass 37 element: symbol valence e# atomic # atomic mass 23 element: sodium symbol valence e# atomic # 10 atomic mass 20 element: symbol valence e# atomic # atomic mass element: symbol valence e# __

Explanation:

Step1: Recall atomic number and mass relationships

Atomic number (number of protons) defines the element. Atomic mass = number of protons + number of neutrons. Valence electrons are in the out - most shell.

Step2: First row second column

Atomic mass = 12, symbol is C (carbon). Atomic number of carbon is 6. Number of neutrons = 12 - 6=6. Electron configuration of carbon is 2,4, so valence electrons = 4.

Step3: First row third column

Atomic mass = 40. Atomic number (from electron configuration 2,8,8,2) is 20, which is calcium (Ca). Number of neutrons = 40 - 20 = 20. Valence electrons = 2.

Step4: First row fourth column

Symbol is H (hydrogen). Atomic number of hydrogen is 1. If number of neutrons is 0, atomic mass is 1. Electron configuration is 1, so valence electrons = 1.

Step5: Second row first column

Atomic number is 20 (from P = 20), element is calcium (Ca), symbol is Ca. Atomic mass = 40, number of neutrons = 40 - 20 = 20. Valence electrons = 2.

Step6: Second row second column

Atomic mass = 11, symbol is B (boron). Atomic number of boron is 5. Number of neutrons = 11 - 5 = 6. Electron configuration of boron is 2,3, so valence electrons = 3.

Step7: Second row third column

Atomic number is 13 (from P = 13), element is aluminum (Al), symbol is Al. Atomic mass = 27, number of neutrons = 27 - 13 = 14. Electron configuration of aluminum is 2,8,3, so valence electrons = 3.

Step8: Second row fourth column

Atomic mass = 32. Atomic number (from electron configuration 2,8,6) is 16, which is sulfur (S). Number of neutrons = 32 - 16 = 16. Valence electrons = 6.

Step9: Third row first column

Atomic mass = 37. Atomic number (from electron configuration 2,8,18,7) is 17, which is chlorine (Cl). Number of neutrons = 37 - 17 = 20. Valence electrons = 7.

Step10: Third row second column

Atomic mass = 23, element is sodium (Na), symbol is Na. Atomic number of sodium is 11. Number of neutrons = 23 - 11 = 12. Electron configuration of sodium is 2,8,1, so valence electrons = 1.

Step11: Third row third column

Atomic number is 10, element is neon (Ne), symbol is Ne. Atomic mass = 20, number of neutrons = 20 - 10 = 10. Electron configuration of neon is 2,8, so valence electrons = 8.

Step12: Third row fourth column

Atomic number is 19 (from P = 19), element is potassium (K), symbol is K. Atomic mass = 19+20 = 39. Electron configuration of potassium is 2,8,8,1, so valence electrons = 1.

Answer:

Atomic #	Atomic Mass	P	N	Element	Symbol	Valence e#
20	40	20	20	Calcium	Ca	2
1	1	1	0	Hydrogen	H	1
20	40	20	20	Calcium	Ca	2
5	11	5	6	Boron	B	3
13	27	13	14	Aluminum	Al	3
16	32	16	16	Sulfur	S	6
17	37	17	20	Chlorine	Cl	7
11	23	11	12	Sodium	Na	1
10	20	10	10	Neon	Ne	8
19	39	19	20	Potassium	K	1