Question

Write the symbols of the ions with the following number of protons and electrons: a. 8 protons, 10 electrons b. 19 protons, 18 electrons c. 35 protons, 36 electrons d. 50 protons, 46 electrons

Short answer

a. \( \text{O}^{2-} \)b. \( \text{K}^{+} \)c. \( \text{Br}^{-} \)d. \( \text{Sn}^{4+} \)

Step-by-step solution

Identify the elements

Use the periodic table to find the elements corresponding to the given number of protons. The number of protons is the atomic number of the element.

Determine the elemental symbols

Find the symbols for elements with 8, 19, 35, and 50 protons. These correspond to oxygen (O), potassium (K), bromine (Br), and tin (Sn) respectively.

Calculate the charge of each ion

Subtract the number of electrons from the number of protons for each element: \[ \text{Charge} = \text{Protons} - \text{Electrons} \text{a.} \text{Charge} = 8 - 10 = -2 \text{b.} \text{Charge} = 19 - 18 = +1 \text{c.} \text{Charge} = 35 - 36 = -1 \text{d.} \text{Charge} = 50 - 46 = +4 \]

Write the ion symbols

Combine the elemental symbols with their respective charges to write the ions: \( \text{a.} \text{O}^{2-} \text{b.} \text{K}^{+} \text{c.} \text{Br}^{-} \text{d.} \text{Sn}^{4+} \)

Key concepts

Atomic Number

The atomic number of an element is fundamental to understanding its identity and properties.
It tells you the number of protons in the nucleus of an atom.
Protons are positively charged particles found in the central part of an atom.
For instance, if an atom has 8 protons, its atomic number is 8. You can find this specific number on the periodic table, which lists all elements by their atomic numbers.
Each element has a unique atomic number.
For instance:

• 8 protons correspond to Oxygen (O).
• 19 protons correspond to Potassium (K).
• 35 protons correspond to Bromine (Br).
• 50 protons correspond to Tin (Sn).

Elemental Symbols

Every element in the periodic table is represented by a unique symbol.
These symbols are usually composed of one or two letters. The first letter is always capitalized, and if there's a second letter, it is lowercased.
For example:

• O represents Oxygen.
• K represents Potassium.
• Br represents Bromine.
• Sn represents Tin.

These symbols make it easier to write and communicate chemical equations and properties.
Elemental symbols give chemists and students a shorthand way to represent elements without writing out full names.

Ion Charges

Ions are atoms or molecules that have gained or lost one or more electrons.
This gain or loss gives the ion a positive or negative charge.
A key concept is to understand how to determine the ion charge:

• If an atom loses electrons, it becomes positively charged (cation). For example, if Potassium (K) loses one electron, it becomes K⁺.
• If an atom gains electrons, it becomes negatively charged (anion). For example, if Oxygen (O) gains two electrons, it becomes O²⁻.

The charge of an ion can be calculated by subtracting the number of electrons from the number of protons.
Using formulas:

• For 8 protons and 10 electrons: 8 - 10 = -2, so the charge is -2.
• For 19 protons and 18 electrons: 19 - 18 = +1, so the charge is +1.

Periodic Table Usage

The periodic table is a vital tool in chemistry.
It systematically arranges all known elements based on their atomic number.
Consider these important uses of the periodic table:

• Identifying Elements: If you know the atomic number, you can find the element easily.
• Determining Properties: Elements in the same column (group) usually have similar chemical properties.
• Calculating Charges: By knowing the elements' usual charges, you can predict how they might form ions.

For example, to find the element with 35 protons, you would locate atomic number 35 on the table, which is Bromine (Br).
The periodic table helps in predicting ally behaviors, making it invaluable for creating and understanding chemical compounds.