Problem 9 - Chemistry A Guided Inquiry

Question

Determine the number of protons, neutrons, and electrons in one \({ }^{1} \mathrm{H}^{+}\) ion. Explain how you found your answer.

Step-by-Step Solution

Answer

The \({ }^{1}\mathrm{H}^{+}\) ion has 1 proton, 0 neutrons, and 0 electrons.

Step 1: Identify the Atomic Number

The atomic number of an atom is given by the subscript in the atomic notation. For \({ }^{1}\mathrm{H}^{+}\), there is no subscript, meaning the atomic number is 1 by default as we are dealing with Hydrogen.

Step 2: Calculate Protons

The number of protons in an atom is equal to the atomic number. Therefore, there is 1 proton in the \({ }^{1}\mathrm{H}^{+}\) ion.

Step 3: Calculate Neutrons

The neutron number is found by subtracting the atomic number from the atomic mass. According to the atomic notation \({ }^{1}\mathrm{H}^{+}\), the atomic mass is 1. As the atomic number is also 1, subtracting these gives us 0. Thus, there are 0 neutrons in the \({ }^{1}\mathrm{H}^{+}\) ion.

Step 4: Calculate Electrons

For a neutral atom, the number of electrons is equal to the number of protons. However, in an ion, the number will be different depending on whether it's a cation or anion. Given the ion \({ }^{1}\mathrm{H}^{+}\), it indicates that it's a cation, so it has 1 less electron than the atomic number. Therefore, the \({ }^{1}\mathrm{H}^{+}\) ion has 0 electrons.

Key Concepts

Protons

Protons are fundamental particles that reside in the nucleus of an atom. They carry a positive charge, symbolized by the sign (+). This positive charge is balanced by the negatively charged electrons, creating a neutral atom when they are equal. The number of protons in an atom determines its atomic number, which is unique to each element. For example, hydrogen has an atomic number of 1, meaning all hydrogen atoms have one proton. This is a defining feature, as the atomic number essentially identifies the element.

• The atomic number is always shown as a subscript in atomic notation.
• The number of protons is equal to the atomic number in a neutral atom.

It is crucial to remember that protons contribute to the atomic mass but not to the identity of isotopes. Understanding protons helps in identifying and distinguishing different elements on the periodic table.

Neutrons

Neutrons, unlike protons, do not carry any charge. They are neutral particles that are also found in the nucleus alongside protons. Neutrons contribute significantly to the mass of an atom but do not affect its charge.

The number of neutrons in an atom can vary even among atoms of the same element, which gives rise to isotopes. Isotopes are atoms of the same element that have different numbers of neutrons. This variance does not change the chemical properties significantly but does affect the physical properties, such as atomic mass.

• The number of neutrons is calculated by subtracting the atomic number from the atomic mass.
• Neutrons play a crucial role in stabilizing the nucleus.

In the given problem of hydrogen ion example, since both the atomic mass and atomic number are 1, there are no neutrons present. It is important to comprehend the role of neutrons in understanding isotopes and nuclear stability.

Electrons

Electrons are negatively charged particles that orbit the nucleus of an atom. They have very little mass compared to protons and neutrons. Though they do not add to the atomic mass, electrons play a significant role in determining the atom's behavior in chemical reactions.

• In a neutral atom, the number of electrons equals the number of protons.
• Electrons occupy energy levels or shells around the nucleus.

Ions are formed when atoms gain or lose electrons, altering the charge balance between protons and electrons. For cations, which have lost electrons, there are fewer electrons than protons. This results in a positive charge. For the hydrogen ion, or hydrogen cation ( extsuperscript{1}H^{+} ), there are 0 electrons, because it has lost its single electron. Understanding electrons is vital to grasping the basics of chemical bonding and ion formation.