Question

For each of the following elements, use the tables on the inside cover of this book to give the chemical symbol, atomic number, and group number of each element, and to specify whether each element is a metal, nonmetal, or metalloid. a. strontium b. iodine c. silicon d. cesium e. sulfur

Short answer

a. Strontium: Sr, atomic number 38, group 2, metal. b. Iodine: I, atomic number 53, group 17, nonmetal. c. Silicon: Si, atomic number 14, group 14, metalloid. d. Cesium: Cs, atomic number 55, group 1, metal. e. Sulfur: S, atomic number 16, group 16, nonmetal.

Step-by-step solution

a. Strontium

Using the periodic table, we find: Chemical Symbol: Sr Atomic Number: 38 Group Number: 2 (also known as Alkaline Earth Metals) Strontium is a metal.

b. Iodine

Using the periodic table, we find: Chemical Symbol: I Atomic Number: 53 Group Number: 17 (also known as Halogens) Iodine is a nonmetal.

c. Silicon

Using the periodic table, we find: Chemical Symbol: Si Atomic Number: 14 Group Number: 14 Silicon is a metalloid.

d. Cesium

Using the periodic table, we find: Chemical Symbol: Cs Atomic Number: 55 Group Number: 1 (also known as Alkali Metals) Cesium is a metal.

e. Sulfur

Using the periodic table, we find: Chemical Symbol: S Atomic Number: 16 Group Number: 16 Sulfur is a nonmetal.

Key concepts

Chemical Symbol

In chemistry, the chemical symbol of an element is a shorthand representation of its name. Usually consisting of one or two letters from the Latin alphabet, these symbols serve as a universal language among scientists, ensuring clarity in the conveyance of information related to elements. For instance, the chemical symbol for hydrogen is 'H', while that for oxygen is 'O'. These symbols are standardized and recognized internationally, and each one corresponds to a unique element.

Understanding chemical symbols is fundamental for students learning chemistry as they are not only used in the periodic table but also in chemical equations, laboratory reports, and scientific literature. One or two-letter symbols may sometimes seem arbitrary or confusing, but they are based on a system that enables you to quickly identify and work with the elements involved in your studies or research.

Atomic Number

The atomic number of an element is a critical concept in chemistry; it defines the number of protons found in the nucleus of an atom of that element. It is denoted by the letter 'Z' and uniquely identifies each element, giving it its place in the periodic table. For example, carbon has an atomic number of 6, which means every carbon atom has 6 protons in its nucleus.

This number is crucial because it also determines the element's chemical properties and its position in the periodic table. Elements are arranged in order of increasing atomic number, and this arrangement reflects patterns in their chemical behavior. In essence, the atomic number is a foundational identifier for elements and a key to understanding how they interact with each other.

Group Number

In the periodic table, elements are arranged not just by their atomic number but also in columns known as 'groups'. The group number of an element refers to its column and is significant because elements within the same group typically share similar chemical properties and valence electron configurations. For example, the noble gases, which are known for their lack of reactivity, all reside in group 18.

The numbers range from 1 to 18 under the current IUPAC (International Union of Pure and Applied Chemistry) nomenclature. Groups are sometimes referred to by older, but still common names, such as the 'alkali metals' for group 1 and 'halogens' for group 17. Although the group number itself does not immediately inform you about the properties of an element, it serves as an effective way of categorizing elements and predicting how they might behave in chemical reactions.

Metals, Nonmetals, and Metalloids

Among their classifications, elements in the periodic table are broadly categorized as metals, nonmetals, or metalloids. Each category has a set of typical properties that distinguish it from the others. Metals, for instance, are usually shiny, malleable, ductile, and good conductors of heat and electricity. They are found to the left of the periodic table and make up the majority of its elements.

On the other hand, nonmetals, which are located to the right side of the periodic table, are often not shiny and are poor conductors of electricity and heat; they are more likely to gain electrons in chemical reactions. The term 'metalloid' is used to describe elements with properties that are intermediate between metals and nonmetals. These elements, like silicon and germanium, are found along the zig-zag line that separates metals and nonmetals on the periodic table. Knowing an element's classification helps in predicting its behavior and the types of compounds it may form.