Question

For each of the following elements, write its chemical symbol, locate it in the periodic table, and indicate whether it is a metal, metalloid, or nonmetal: (a) chromi\(\mathrm{um}_{1}\) (b) helium, (c) phosphorus, (d) zinc, (e) magnesium, (f) bromine, \((g)\) arsenic.

Short answer

(a) Chromium: Chemical symbol: Cr; Group 6, Period 4; Metal. (b) Helium: Chemical symbol: He; Group 18, Period 1; Nonmetal. (c) Phosphorus: Chemical symbol: P; Group 15, Period 3; Nonmetal. (d) Zinc: Chemical symbol: Zn; Group 12, Period 4; Metal. (e) Magnesium: Chemical symbol: Mg; Group 2, Period 3; Metal. (f) Bromine: Chemical symbol: Br; Group 17, Period 4; Nonmetal. (g) Arsenic: Chemical symbol: As; Group 15, Period 4; Metalloid.

Step-by-step solution

(a) Chromium

The chemical symbol for Chromium is Cr. It is located in Group 6 and Period 4 of the periodic table, making it a transition metal. As a metal, chromium has high electrical and thermal conductivity.

(b) Helium

The chemical symbol for Helium is He. It is located in Group 18 and Period 1 of the periodic table, making it a noble gas. As a nonmetal, helium is colorless, odorless, tasteless, and has low reactivity.

(c) Phosphorus

The chemical symbol for Phosphorus is P. It is located in Group 15 and Period 3 of the periodic table, making it a nonmetal. Phosphorus is known for its distinct red and white allotropes.

(d) Zinc

The chemical symbol for Zinc is Zn. It is located in Group 12 and Period 4 of the periodic table, making it a transition metal. As a metal, zinc is a good conductor of electricity and is often used for galvanizing steel.

(e) Magnesium

The chemical symbol for Magnesium is Mg. It is located in Group 2 and Period 3 of the periodic table, making it an alkaline earth metal. Magnesium is a silver-white metal known for its lightness, strength, and relatively high reactivity.

(f) Bromine

The chemical symbol for Bromine is Br. It is located in Group 17 and Period 4 of the periodic table, making it a halogen. As a nonmetal, bromine exists as a reddish-brown liquid at room temperature and is highly reactive.

(g) Arsenic

The chemical symbol for Arsenic is As. It is located in Group 15 and Period 4 of the periodic table, making it a metalloid. Arsenic exhibits properties of both metals and nonmetals, making it useful for various applications such as semiconductors, but it is also a well-known poison.

Key concepts

Chemical Symbols

Every chemical element has a unique symbol that is used worldwide to represent the element on the periodic table. These symbols are one- or two-letter abbreviations, often derived from the element’s English or Latin name. For example, Chromium is represented by "Cr," and Helium is depicted as "He." This system of chemical symbols simplifies the writing and identification of elements.

Knowing these symbols is crucial for understanding chemical formulas, equations, and scientific discussions. It also helps in quickly identifying an element's properties, group classifications, and the location in the periodic table with just a glance.

Element Classification

Elements on the periodic table are classified based on their properties and behaviors. The main categories include metals, nonmetals, and metalloids.

• Metals: These elements are typically hard, shiny, and good conductors of heat and electricity. They are usually malleable, meaning they can be hammered into thin sheets.
• Nonmetals: These are found on the right side of the periodic table (except hydrogen) and have properties opposite to metals. They are not good conductors of heat and electricity and are often brittle.
• Metalloids: As the name suggests, these elements have mixed properties of both metals and nonmetals. They are often used in semiconductors due to their intermediate conductivity.

The classification helps determine how an element might react in chemical processes and indicates its potential applications in industries.

Group and Period Location

The location of an element on the periodic table is determined by its group and period, which helps predict its properties and behaviors.

Groups are the vertical columns on the periodic table. Elements within the same group typically have similar properties and behaviors due to having the same number of valence electrons.

Periods are the horizontal rows. They indicate the number of electron shells, with the period number matching the highest energy level an electron in an element occupies. For instance, Chromium is in Group 6 and Period 4, indicating it has similar properties with other elements in Group 6 and has four electron shells. Understanding group and period locations are essential for anticipating chemical reactivity and forming bonds.

Metals, Metalloids, and Nonmetals

The periodic table categorizes elements into metals, metalloids, and nonmetals, which each have distinct physical and chemical properties:

• Metals: Typically occupy the left and central parts of the periodic table. They are conductive, malleable, and often have high melting points. Examples include Zinc and Magnesium.
• Metalloids: Found between metals and nonmetals, these elements exhibit mixed properties. Arsenic is a classic metalloid, used in semiconductors due to its moderate conductivity.
• Nonmetals: Positioned on the right side of the table, nonmetals like Helium and Bromine are usually poor conductors and are more diverse in terms of state – gases, solids, or liquids.

This classification not only aids in understanding elemental behavior but also their applications, from constructing electronic devices to forming essential compounds for biological processes.