Question

atomic structure and valence electron practice
the purpose of this assignment is to help you become more familiar with the atomic structure of some common elements by completing the chart below. for each element you have been given enough information to fill all of the blanks.
isotopic name element symbol atomic # mass # # protons # neutrons # electrons # valence elec.
2 4
12 12
30 65
br 80 35
aluminum - 27 13 14
u 146 92
11 12
krypton - 84 48 36
ca 40 20
ag 47 61

Explanation:

Step1: Recall atomic structure relationships

Atomic number = # Protons = # Electrons (for neutral atoms). Mass number = # Protons+# Neutrons. Valence - electrons can be determined from the electron - configuration which is related to the group number in the periodic table.

Step2: First row (Helium)

Atomic number 2 means the element is Helium (He). # Protons = 2, # Electrons = 2. # Neutrons=Mass number - # Protons = 4 - 2=2. Helium has 2 valence electrons (it is in group 18 and has a full outer shell).

Step3: Second row (Magnesium)

Atomic number 12 means the element is Magnesium (Mg). Mass number = # Protons+# Neutrons = 12 + 12=24. # Electrons = 12. Magnesium is in group 2, so it has 2 valence electrons.

Step4: Third row (Zinc)

Atomic number 30 means the element is Zinc (Zn). # Protons = 30, # Electrons = 30. # Neutrons=Mass number - # Protons = 65 - 30 = 35. Zinc is in group 12 and has 2 valence electrons.

Step5: Fourth row (Bromine)

Atomic number of Br is 35. Mass number = 80. # Protons = 35, # Neutrons=80 - 35 = 45. # Electrons = 35. Bromine is in group 17, so it has 7 valence electrons.

Step6: Fifth row (Aluminum - 27)

Element symbol is Al. Atomic number = # Protons = 13. Mass number = 27. # Neutrons = 14. # Electrons = 13. Aluminum is in group 13, so it has 3 valence electrons.

Step7: Sixth row (Uranium)

Element symbol is U. Atomic number = 92. Mass number= # Protons+# Neutrons = 92+146 = 238. # Electrons = 92. Uranium is a transition - metal - like element in the actinide series. Its valence electrons are more complex to determine exactly from simple group - based rules, but in a basic sense, it can have variable valence. For a simple approach, we can consider its outer - shell electrons in some of its common oxidation states, but a full treatment requires more advanced knowledge. Let's assume we are looking at the basic electron - configuration and say it has 6 valence electrons considering its position in the periodic table.

Step8: Seventh row (Sodium)

Atomic number 11 means the element is Sodium (Na). Mass number = # Protons+# Neutrons = 11 + 12=23. # Electrons = 11. Sodium is in group 1, so it has 1 valence electron.

Step9: Eighth row (Krypton - 84)

Element symbol is Kr. Atomic number = 36. Mass number = 84. # Protons = 36, # Neutrons=84 - 36 = 48. # Electrons = 36. Krypton is in group 18, so it has 8 valence electrons.

Step10: Ninth row (Calcium)

Atomic number 20 means the element is Calcium (Ca). Mass number = 40. # Protons = 20, # Neutrons=40 - 20 = 20. # Electrons = 20. Calcium is in group 2, so it has 2 valence electrons.

Step11: Tenth row (Silver)

Element symbol is Ag. Atomic number = 47. Mass number = # Protons+# Neutrons = 47+61 = 108. # Electrons = 47. Silver is in group 11, so it has 1 valence electron.

Answer:

Isotopic Name	Element Symbol	Atomic #	Mass #	# Protons	# Neutrons	# Electrons	# Valence elec.
Magnesium - 24	Mg	12	24	12	12	12	2
Zinc - 65	Zn	30	65	30	35	30	2
Bromine - 80	Br	35	80	35	45	35	7
Aluminum - 27	Al	13	27	13	14	13	3
Uranium - 238	U	92	238	92	146	92	6
Sodium - 23	Na	11	23	11	12	11	1
Krypton - 84	Kr	36	84	36	48	36	8
Calcium - 40	Ca	20	40	20	20	20	2
Silver - 108	Ag	47	108	47	61	47	1