Chlorine

Definition

Chlorine is a highly reactive, greenish-yellow gas that is one of the five halogens in the periodic table. It is an essential element in many chemical processes and compounds, with wide-ranging applications in various industries and everyday life.

5 Must Know Facts For Your Next Test

1. Chlorine has an atomic number of 17 and an atomic mass of 35.45 g/mol, making it the second lightest halogen after fluorine.
2. Chlorine is a highly reactive element and is typically found in nature combined with other elements, such as in the form of sodium chloride (table salt).
3. Chlorine is used in the production of many common household and industrial products, including water treatment, disinfectants, and plastics.
4. Chlorine gas is toxic and can be dangerous if inhaled or exposed to in high concentrations, as it can cause severe respiratory distress and other health issues.
5. The periodic trends of the halogens, including chlorine, show that they become less reactive and have higher melting and boiling points as you move down the group.

Review Questions

• Explain how the atomic structure and symbolism of chlorine relate to its position in the periodic table and its chemical properties.
  • Chlorine is a member of the halogen group in the periodic table, with an atomic number of 17 and an electron configuration of [Ne] 3s^2 3p^5. This means that chlorine has seven valence electrons and is highly reactive, as it tends to form stable compounds by gaining one electron to achieve a full octet. Chlorine's position in the periodic table, as the second lightest halogen, influences its chemical properties, such as its high reactivity, oxidation states, and tendency to form diatomic molecules like Cl₂.
• Describe how the periodic variations in element properties, such as electronegativity and ionization energy, affect the behavior and reactivity of chlorine.
  • As you move down the halogen group in the periodic table, the elements become less electronegative and have lower ionization energies. This means that chlorine, being higher in the group, is more electronegative and has a higher ionization energy compared to the other halogens. These periodic trends contribute to chlorine's high reactivity, as it readily forms ionic or covalent bonds with other elements in order to achieve a stable octet configuration. The periodic variations in element properties also influence chlorine's oxidation states, as it can form a range of compounds with different oxidation numbers.
• Analyze the role of chlorine in the context of chemical nomenclature, formula mass, and the mole concept, and how these concepts are interconnected.
  • In the context of chemical nomenclature, chlorine can form a variety of compounds, such as ionic salts (e.g., sodium chloride, NaCl) and covalent molecules (e.g., hydrogen chloride, HCl). The molar mass of chlorine, which is approximately 35.45 g/mol, is an important factor in determining the formula mass of these chlorine-containing compounds. The mole concept, which relates the number of particles (atoms, molecules, or ions) to the mass of a substance, is crucial for understanding the quantitative relationships between chlorine and the other elements in these compounds. These interconnected concepts of nomenclature, formula mass, and the mole are essential for predicting the properties and behavior of chlorine-based substances.

Related terms

Halogen: A group of five elements (fluorine, chlorine, bromine, iodine, and astatine) that are highly reactive nonmetals and form negative ions with a single electron.

Oxidation State:

The degree of oxidation of an atom in a chemical compound, represented by a number that indicates the number of electrons the atom has lost or gained.

Diatomic Molecule: A molecule consisting of two atoms of the same element, such as the chlorine molecule (Cl₂).