Question

How many electrons are in the valence shell of each atom? (a) Carbon (b) Nitrogen (c) Chlorine (d) Aluminum

Short answer

Question: How many valence electrons are in the following atoms: (a) Carbon (C) (b) Nitrogen (N) (c) Chlorine (Cl) (d) Aluminum (Al) Answer: (a) Carbon: 4 valence electrons (b) Nitrogen: 5 valence electrons (c) Chlorine: 7 valence electrons (d) Aluminum: 3 valence electrons

Step-by-step solution

Find the atomic numbers

To determine the atomic numbers of each atom, we can refer to the periodic table. The atomic numbers are: - Carbon (C): 6 - Nitrogen (N): 7 - Chlorine (Cl): 17 - Aluminum (Al): 13

Determine the electron configurations

To determine the electron configuration of each atom, we can use the atomic numbers as follows: - For Carbon (C), the atomic number is 6, the electron configuration is 1s^2 2s^2 2p^2. - For Nitrogen (N), the atomic number is 7, the electron configuration is 1s^2 2s^2 2p^3. - For Chlorine (Cl), the atomic number is 17, the electron configuration is 1s^2 2s^2 2p^6 3s^2 3p^5. - For Aluminum (Al), the atomic number is 13, the electron configuration is 1s^2 2s^2 2p^6 3s^2 3p^1.

Determine the valence electrons

The valence electrons are the electrons in the outermost energy level (shell). We can look at the electron configuration for each atom to determine the number of valence electrons: - Carbon (C): 2s^2 2p^2 => 4 valence electrons. - Nitrogen (N): 2s^2 2p^3 => 5 valence electrons. - Chlorine (Cl): 3s^2 3p^5 => 7 valence electrons. - Aluminum (Al): 3s^2 3p^1 => 3 valence electrons. So, the number of valence electrons for each atom is: (a) Carbon: 4 (b) Nitrogen: 5 (c) Chlorine: 7 (d) Aluminum: 3

Key concepts

Electron Configuration

Electron configuration is a way of representing how electrons are distributed in an atom. It is crucial for understanding many properties of elements, including how they bond with other elements. The configuration tells us which orbitals the electrons are in. Each element has a unique electron configuration, determined by its number of electrons.

The electron configuration helps to visualize the arrangement of electrons among the orbitals, using notations such as 1s, 2s, 2p, 3s, and so on. These notations tell us the principal energy level (the number in front), the sublevel type (s, p, d, f), and the number of electrons in those sublevels (shown as superscript numbers).

For instance, the electron configuration for carbon is 1s² 2s² 2p². This means carbon has 2 electrons in the 1s sublevel, 2 in the 2s sublevel, and 2 in the 2p sublevel. This notation allows chemists to predict chemical bonding patterns and reactions.

Atomic Number

The atomic number is the number of protons in the nucleus of an atom. It defines the element and determines the chemical nature of that element. Each atom has an equal number of protons and electrons, meaning the atomic number also tells us how many electrons are present in a neutral atom.

For example, the atomic number of carbon is 6, which means there are 6 protons and, in a neutral state, 6 electrons. Understanding the atomic number is fundamental to determining the electron configuration of atoms.

By using the periodic table, we can easily find the atomic number of any element. This is often represented as a whole number accompanying the element's symbol on the table, situated above the element description.

Periodic Table

The periodic table is a chart that organizes chemical elements based on their atomic number, electron configurations, and recurring chemical properties. It's an essential tool for chemists and helps predict the properties and behaviors of elements.

Elements are arranged in rows called periods and columns known as groups. Elements in a particular group typically have similar properties and valence electron configurations. For instance, elements in Group 1 (such as lithium and sodium) have one electron in their outermost shell and tend to be highly reactive.

The periodic table allows us to identify trends, such as electronegativity, ionization energies, and atomic radii, and helps predict the types of bonds atoms can form with each other.

Chemical Elements

Chemical elements are the simplest form of substances that cannot be broken down into simpler substances by chemical means. Each element is defined by its atomic number, which indicates the number of protons in its nucleus.

Elements are represented by unique symbols, usually derived from their English or Latin names. For example, C stands for carbon, N for nitrogen, Cl for chlorine, and Al for aluminum. These symbols are widely used in chemical equations and formulas.

Understanding elements and their properties is essential for studying chemistry. It allows us to comprehend how compounds form, how reactions occur, and how different materials are composed. Each element's distinct nature arises from its specific electron configuration, influencing how it interacts with other elements.