Question

According to Rutherford's model of the atom, how many electrons would be found in each of the following atoms? a. lithium, which has 3 protons in its nucleus b. magnesium, which has 12 protons in its nucleus

Short answer

Lithium has 3 electrons. Magnesium has 12 electrons.

Step-by-step solution

Understanding Rutherford's Model

Rutherford's model of the atom posits that an atom consists of a central nucleus surrounded by electrons. The number of electrons in an atom is equal to the number of protons in the nucleus to maintain electrical neutrality. This is because protons have a positive charge and electrons have a negative charge, and an atom is neutral when these charges balance out.

Determining the Number of Electrons in Lithium

Since lithium has 3 protons in its nucleus, it must also have 3 electrons surrounding the nucleus to balance the positive charge of the protons. Therefore, lithium has 3 electrons.

Determining the Number of Electrons in Magnesium

Similarly, since magnesium has 12 protons in its nucleus, it will also have 12 electrons to maintain electrical neutrality. Therefore, magnesium has 12 electrons.

Key concepts

Atomic Structure

The structure of an atom is fundamental to understanding chemistry. At the heart of Rutherford's model lies the nucleus, a dense region centrally located within the atom. This nucleus is composed of protons, which carry a positive charge, and neutrons, which are neutral particles. Surrounding the nucleus is a cloud of electrons, negatively charged particles that move rapidly in various orbitals.

As per Rutherford's atomic theory, these electrons travel around the nucleus much like planets orbit the sun, although modern quantum mechanics has refined this view to consider probabilistic regions where electrons are likely to be found, rather than fixed orbits. The key point is that each atom contains an equal number of protons and electrons, imparting a state of electrically neutral charge to the atom when in its elemental form. For example, the lithium atom, with 3 protons in the nucleus, will also have 3 electrons in order to maintain this balance. The atomic structure is central to the chemical behavior of elements and their interactions with one another.

Electrical Neutrality in Atoms

Electrically, atoms are neutral entities. This neutrality comes from the balance of positively charged protons in the nucleus and the negatively charged electrons surrounding it.

Each proton carries a positive charge equal in magnitude but opposite in sign to the negative charge of an electron. When the number of protons equals the number of electrons, their charges cancel out, resulting in a neutral charge for the atom. This is crucial to the stability of an atom. For example, in the case of magnesium, which harbors 12 protons, there must be 12 electrons to counterbalance the positive charge, ensuring the atom's neutrality. Electrical neutrality is fundamental to the concept of atoms, influencing the way they bond and interact to form molecules.

Protons and Electrons Relationship

The relationship between protons and electrons is a defining characteristic of an atom's identity and properties. Protons, found in the nucleus, define the atomic number of an element—the number of protons is unique to each element and determines where it falls on the periodic table. Electrons, on the other hand, play a significant role in chemical bonding and the atom's reactivity.

The intrinsic balance between the number of protons and electrons means that atoms strive to maintain equal quantities of each. For instance, in both lithium and magnesium's neutral state, they equilibrate the number of protons with an identical number of electrons, 3 and 12, respectively. When this balance is disturbed, an atom becomes an ion, carrying a net charge and leading to the potential for ionic bonding. Understanding the proton-electron relationship is critical to grasp how atoms form bonds to create compounds and the ensuing chemical reactions that occur.