Question

practice: atomic calculations
part 1 atomic structure
1 draw four protons in the atom to the right. label them with their charge.
2 draw five neutrons in the atom to the right. label them with their charge.
3 draw four electrons in the atom to the right. place two on the first energy
level and two on the second. label them with their charge
4 what element did you just draw?
5 how do you know?
part 2 periodic table
6 label each part of the periodic table notation shown to the right.
7 how do you know the number of protons in an atom?
8 how do you know the number of neutrons?
9 how do you know the number of electrons?
part 3 atomic calculations complete the chart below
10.
element atomic # mass # # of p⁺ # of n⁰ # of e⁻
3 7
p 31
35 17
28 31
k 39
ag 61
1 1
14 14
74 110
ne 10

Answer:

Part 1: Atomic Structure

1. Drawing Protons

• Explanation: Protons are positively charged and located in the nucleus. We need to draw 4 protons in the nucleus (the central circle) and label them with \( + \).
• Action: In the central nucleus (the inner circle), draw 4 small circles or dots and label each with \( + \) (representing the positive charge of protons).

2. Drawing Neutrons

• Explanation: Neutrons are neutral (no charge) and also in the nucleus. We draw 5 neutrons in the nucleus and label them with \( 0 \) (since they have no charge).
• Action: In the central nucleus, draw 5 small circles or dots (along with the protons) and label each with \( 0 \) (representing the neutral charge of neutrons).

3. Drawing Electrons

• Explanation: Electrons are negatively charged and orbit the nucleus in energy levels. The first energy level (closest to the nucleus) can hold up to 2 electrons, and the second can hold up to 8 (but we have 2 here). We place 2 electrons on the first energy level (the inner electron shell) and 2 on the second (the outer electron shell) and label them with \( - \).
• Action: On the first energy level (the inner ring around the nucleus), draw 2 small circles or dots and label each with \( - \). On the second energy level (the outer ring), draw 2 small circles or dots and label each with \( - \).

4. Identifying the Element

• Explanation: The number of protons (atomic number) determines the element. We have 4 protons, so we look at the periodic table for the element with atomic number 4.
• Answer: Beryllium (Be)

5. Reasoning for the Element

• Explanation: The atomic number (number of protons) is unique to each element. Since we drew 4 protons, the atomic number is 4, which corresponds to Beryllium on the periodic table.
• Answer: The element is Beryllium because the number of protons (atomic number) is 4, and the element with atomic number 4 is Beryllium.

Part 2: Periodic Table

6. Labeling Periodic Table Notation (for Nitrogen, \( \ce{N} \) with atomic number 7, mass number ~14.01)

• Explanation: The periodic table notation has several parts: the atomic number (top left), the element symbol (middle), the element name (bottom), and the atomic mass (bottom right).
• Labels:
• Top number (7): Atomic number (number of protons)
• Middle letter (N): Element symbol
• Bottom word (Nitrogen): Element name
• Bottom number (14.01): Atomic mass (average mass of the element's isotopes)

7. Number of Protons in an Atom

• Explanation: The atomic number (the number at the top of the element's box on the periodic table) is equal to the number of protons in an atom of that element.
• Answer: The number of protons is equal to the atomic number (the top number in the element's box on the periodic table).

8. Number of Neutrons in an Atom

• Explanation: The mass number (rounded atomic mass) minus the atomic number gives the number of neutrons (since mass number = protons + neutrons).
• Formula: \( \text{Number of neutrons} = \text{Mass number} - \text{Atomic number} \)
• Answer: To find the number of neutrons, subtract the atomic number (number of protons) from the mass number (rounded atomic mass). So, \( \text{Neutrons} = \text{Mass number} - \text{Atomic number} \).

9. Number of Electrons in an Atom (for a neutral atom)

• Explanation: In a neutral atom, the number of electrons is equal to the number of protons (to balance the positive and negative charges).
• Answer: For a neutral atom, the number of electrons is equal to the number of protons (atomic number), so electrons = protons (atomic number).

Part 3: Atomic Calculations (Completing the Chart)

We use the following relationships:

• Atomic number (\( Z \)) = number of protons (\( p^+ \)) = number of electrons (\( e^- \)) (for neutral atoms)
• Mass number (\( A \)) = number of protons (\( p^+ \)) + number of neutrons (\( n^0 \))

So, \( n^0 = A - Z \)

Let's complete each row:

Element	Atomic # (\( Z \))	Mass # (\( A \))	# of \( p^+ \)	# of \( n^0 \) (\( A - Z \))	# of \( e^- \) (\( Z \))
2. P	15 (Atomic # of P)	31	15	\( 31 - 15 = 16 \)	15
3.	17 (Atomic # of Cl)	35	17	\( 35 - 17 = 18 \)	17
4.	28	\( 28 + 31 = 59 \)	28	31	28
5. K	19 (Atomic # of K)	39	19	\( 39 - 19 = 20 \)	19
6. Ag	47 (Atomic # of Ag)	\( 47 + 61 = 108 \)	47	61	47
7.	1	1	1	\( 1 - 1 = 0 \)	1
8.	14 (Atomic # of Si)	\( 14 + 14 = 28 \)	14	14	14
9.	74 (Atomic # of W)	\( 74 + 110 = 184 \)	74	110	74
10. Ne	10 (Atomic # of Ne)	\( 10 + 10 = 20 \)	10	10	10

Detailed Calculations for Each Row:

1. First Row (Atomic # 3, Mass # 7):

• \( p^+ = 3 \) (atomic #)
• \( n^0 = 7 - 3 = 4 \)
• \( e^- = 3 \) (neutral atom, so \( e^- = p^+ \))

1. Phosphorus (P):

• Atomic # of P is 15, so \( p^+ = 15 \)
• \( n^0 = 31 - 15 = 16 \)
• \( e^- = 15 \)

1. Chlorine (Cl, \( p^+ = 17 \)):

• Atomic # = 17, so \( Z = 17 \)
• \( n^0 = 35 - 17 = 18 \)
• \( e^- = 17 \)

1. Atomic # 28, \( n^0 = 31 \):

• \( A = 28 + 31 = 59 \)
• \( p^+ = 28 \)
• \( e^- = 28 \)

1. Potassium (K):

• Atomic # of K is 19, so \( p^+ = 19 \)
• \( n^0 = 39 - 19 = 20 \)
• \( e^- = 19 \)

1. Silver (Ag):

• Atomic # of Ag is 47, so \( p^+ = 47 \)
• \( A = 47 + 61 = 108 \)
• \( e^- = 47 \)

1. Hydrogen (H, \( p^+ = 1 \), \( A = 1 \)):

• \( n^0 = 1 - 1 = 0 \)
• \( e^- = 1 \)

1. Silicon (Si, \( e^- = 14 \), \( n^0 = 14 \)):

• \( p^+ = 14 \) (since \( e^- = p^+ \) in neutral atom)
• \( A = 14 + 14 = 28 \)
• Atomic # = 14

1. Tungsten (W, \( p^+ = 74 \), \( n^0 = 110 \)):

• \( A = 74 + 110 = 184 \)
• \( e^- = 74 \) (neutral atom)

1. Neon (Ne):

• Atomic # of Ne is 10, so \( p^+ = 10 \)
• \( A = 10 + 10 = 20 \)
• \( e^- = 10 \)