Problem 75 - Chemistry Matter and Change

Question

For each chemical symbol, determine the number of protons and electrons an atom of the element contains. \begin{equation} \begin{array}{ll}{\text { a. } V} & {\text { c. Ir }} \\ {\text { b. Mn }} & {\text { d. } S}\end{array} \end{equation}

Step-by-Step Solution

Answer

V: 23 protons/electrons, Mn: 25 protons/electrons, Ir: 77 protons/electrons, S: 16 protons/electrons.

Step 1: Understand Atomic Structure

For a neutral atom, the number of protons equals the number of electrons. The atomic number of an element, which can be found on the periodic table, indicates the number of protons in one atom of that element.

Step 2: Find Atomic Number of V (Vanadium)

Vanadium has an atomic number of 23, which means a neutral vanadium atom has 23 protons and 23 electrons.

Step 3: Find Atomic Number of Mn (Manganese)

Manganese has an atomic number of 25, indicating that a neutral manganese atom contains 25 protons and 25 electrons.

Step 4: Find Atomic Number of Ir (Iridium)

Iridium's atomic number is 77, so a neutral iridium atom possesses 77 protons and 77 electrons.

Step 5: Find Atomic Number of S (Sulfur)

Sulfur has an atomic number of 16, which means a neutral sulfur atom has 16 protons and 16 electrons.

Key Concepts

Understanding Protons

Protons are one of the fundamental particles that make up an atom. They are located in the atom's nucleus and have a positive electric charge. The main role of protons is to define the identity of an atom, as the number of protons in the nucleus determines the element to which the atom belongs. This is expressed as the atomic number on the periodic table.

Here are a few key points to remember about protons:

• Protons have a positive charge (+1).
• The number of protons in an atom is equal to the atomic number.
• Changing the number of protons transforms the atom into a different element.
• Protons, along with neutrons, contribute to the majority of an atom's mass.

In a neutral atom, the number of protons is equal to the number of electrons. This balance of charges is what keeps an atom electrically neutral. For example, an atom of vanadium, with an atomic number of 23, contains 23 protons.

Electrons: The Negative Charge of Atoms

Electrons are subatomic particles that orbit the nucleus of an atom. They have a negative charge, which is equal in magnitude but opposite to the positive charge of protons. The distribution of electrons in an atom is what plays a crucial role in chemical reactions and bonding.

Some important aspects of electrons include:

• Electrons have a negative charge (-1).
• They are much lighter than protons and neutrons.
• Their arrangement in specific energy levels or "shells" determines an atom’s chemical properties.
• In a neutral atom, the number of electrons equals the number of protons.

For example, a neutral atom of manganese has an atomic number of 25, which means it has 25 electrons orbiting its nucleus. Electrons are capable of moving between energy levels or being shared/transferred between atoms during chemical reactions.

The Significance of Atomic Number

The atomic number is a crucial concept in understanding an element's identity. It is the number of protons in the nucleus of an atom and is unique for each element, providing its distinct identity on the periodic table.

Atomic number carries several significant implications:

• It defines the element. For example, sulfur has an atomic number of 16, indicating it has 16 protons and is placed accordingly on the periodic table.
• The atomic number also determines the chemical properties and behavior of an element.
• Based on the atomic number, we can also find the number of electrons in a neutral atom.
• It helps in identifying isotopes—atoms with the same number of protons but different numbers of neutrons.

Understanding atomic numbers helps in exploring chemical reactions and bonding. For instance, iridium, with an atomic number of 77, will always have 77 protons, and in its neutral state, it will also have 77 electrons. This defines its position and determines its properties within the periodic table.