Question

How many protons are in the nucleus of an atom of each element? (a) \(\mathrm{Ar}\) (b) \(\mathrm{Sn}\) (c) \(\mathrm{Xe}\) (d) \(\mathrm{O}\) (e) \(\mathrm{Tl}\)

Short answer

The number of protons for each element is as follows: \text{Ar}: 18, \text{Sn}: 50, \text{Xe}: 54, \text{O}: 8, \text{Tl}: 81.

Step-by-step solution

Identify Atomic Number of Argon (\text{Ar})

Look up Argon in the periodic table to find its atomic number, which represents the number of protons in the nucleus of the atom.

Identify Atomic Number of Tin (\text{Sn})

Look up Tin in the periodic table to find its atomic number, which represents the number of protons in the nucleus of the atom.

Identify Atomic Number of Xenon (\text{Xe})

Look up Xenon in the periodic table to find its atomic number, which represents the number of protons in the nucleus of the atom.

Identify Atomic Number of Oxygen (\text{O})

Look up Oxygen in the periodic table to find its atomic number, which represents the number of protons in the nucleus of the atom.

Identify Atomic Number of Thallium (\text{Tl})

Look up Thallium in the periodic table to find its atomic number, which represents the number of protons in the nucleus of the atom.

Key concepts

Protons in the Nucleus

Understanding the number of protons in the nucleus is essential for identifying different elements. Protons are positively charged particles found within the atomic nucleus and their number is fundamental to the atomic structure. This number, known as the atomic number, is uniquely assigned to each element. For instance, Argon (Ar) has 18 protons, Tin (Sn) has 50 protons, Xenon (Xe) has 54 protons, Oxygen (O) has 8 protons, and Thallium (Tl) has 81 protons.

The atomic number determines the chemical properties of the element and its placement on the periodic table. Each element has a different number of protons, which means no two elements share the same atomic number. This helps in the identification and characterization of the elements, making protons the identity marker within the atomic nucleus.

Periodic Table

The periodic table is a tabular arrangement of all known chemical elements, organized by increasing atomic number, electron configurations, and recurring chemical properties. Elements are listed in rows called periods and columns called groups. Elements with similar chemical behaviors appear in the same column.

And it's not just a table, but a powerful tool for predicting the properties of elements. For example, elements in the same group typically have the same number of electrons in their outermost shell, which predicts similar reactivity patterns. The atomic number that we used to identify the number of protons in the nucleus in our exercise is prominently displayed with each element on the periodic table, underscoring its fundamental role in chemical science.

Atomic Structure

Atomic structure defines the organization of subatomic particles—protons, neutrons, and electrons—in an atom. Protons and neutrons make up the atom's nucleus, and electrons orbit this nucleus in various energy levels.

The number of protons (atomic number) determines the element's identity, while the number of neutrons can vary, leading to different isotopes of the same element. Electrons orbit at various distances from the nucleus, based on their energy levels, and their arrangement can influence an element's chemical properties and reactivity.

Key Layers of an Atom

At the center, the nucleus contains the protons and neutrons. Surrounding the nucleus are the electron shells, where electrons reside. The behavior of these electrons in their respective shells explains why elements interact and combine in the ways that they do, which is the basis for chemistry.

Chemical Elements

Chemical elements are pure substances made up of only one type of atom, characterized by a specific number of protons in their nuclei. The diversity in the properties of chemical elements comes from variations in their atomic structure—mainly the number of protons and electrons. For instance, some elements are metals, others non-metals, or metalloids, based on these atomic characteristics.

Each element's unique features determine how it interacts with other elements to form compounds through chemical reactions. These interactions are predictable based on an element's placement in the periodic table and its electron configuration, indicating the deep interconnection between the concepts of atomic structure, chemical elements, and the periodic table itself.