Question

1. draw a bohr model for neutral li and the ion li+1
2. what are valence electrons?
3. how many electrons fit in each shell (energy level) around an atom?
4. complete the following table.

element	# of protons	# of neutrons	# of electrons	charge	atomic mass	atomic number
aluminum	13			0	27	13

1. explain why carbon - 13 and carbon - 14 are not two different elements?
2. fill out the following chart:

# of protons =	# of neutrons =	# of electrons =	# of valence electrons=	atomic number of element:	mass number of element:

Explanation:

Step1: Define valence electrons

Valence electrons are outermost electrons.

Step2: Determine electron - shell capacities

Use the \(2n^{2}\) rule.

Step3: Calculate neutrons and electrons for Boron and Aluminum

Use atomic - mass and charge relationships.

Step4: Explain isotopes

Same proton number defines element.

Step5: Calculate values for Neon + 3 ion

Use atomic number, charge, and mass - number relationships.

Answer:

1. Valence electrons are the electrons in the outermost shell (highest - energy level) of an atom. They are involved in chemical bonding.
2. The first shell can hold a maximum of 2 electrons. The second shell can hold a maximum of 8 electrons. The third shell can hold a maximum of 18 electrons (but often fills to 8 in many common elements before moving to the next shell), and in general, the \(n^{th}\) shell can hold a maximum of \(2n^{2}\) electrons.

12.
For Boron:

• Number of neutrons: Atomic mass - Atomic number = 11 - 5=6
• Number of electrons: Since the charge is + 1, number of electrons = number of protons - charge = 5 - 1 = 4

For Aluminum:

• Number of neutrons: Atomic mass - Atomic number = 27 - 13 = 14
• Number of electrons: Since the charge is 0, number of electrons = number of protons = 13

Element	# of Protons	# of Neutrons	# of Electrons	Charge	Atomic Mass	Atomic Number
Aluminum	13	14	13	0	27	13

1. Carbon - 13 and Carbon - 14 are not two different elements because they have the same number of protons (6). The number of protons (atomic number) defines the element. They are isotopes of carbon, which means they have different numbers of neutrons (Carbon - 13 has 7 neutrons and Carbon - 14 has 8 neutrons), but the same atomic number.

14.

• For Neon with a charge of +3:
• Atomic number of Neon is 10, so number of protons = 10
• Mass number of Neon is typically 20, so number of neutrons = Mass number - Atomic number = 20 - 10 = 10
• Number of electrons = number of protons - charge = 10 - 3 = 7
• For a neutral Neon, the electron - configuration is 2, 8. After losing 3 electrons (due to +3 charge), the electron - configuration is 2, 5. So number of valence electrons = 5

# of Protons	# of Neutrons	# of Electrons	# of Valence Electrons	Atomic Number of Element	Mass Number of Element