Question

Refer to the periodic table and find the atomic number for each of the following: (a) hydrogen (b) boron (c) aluminum (d) titanium (e) arsenic (f) strontium (g) tin (h) bismuth

Short answer

Hydrogen: 1, Boron: 5, Aluminum: 13, Titanium: 22, Arsenic: 33, Strontium: 38, Tin: 50, Bismuth: 83.

Step-by-step solution

Identify Hydrogen

Locate hydrogen on the periodic table. Hydrogen is the first element, so its atomic number is 1.

Identify Boron

Find boron on the periodic table. Boron is in group 13 and period 2, with an atomic number of 5.

Identify Aluminum

Look for aluminum on the periodic table. It is found in group 13 and period 3, with an atomic number of 13.

Identify Titanium

Locate titanium in the periodic table. Titanium is in group 4 and period 4, with an atomic number of 22.

Identify Arsenic

Find arsenic on the periodic table. It is in group 15 and period 4, and its atomic number is 33.

Identify Strontium

Locate strontium in the periodic table. Strontium is in group 2 and period 5, with an atomic number of 38.

Identify Tin

Find tin on the periodic table. It is in group 14 and period 5, with an atomic number of 50.

Identify Bismuth

Locate bismuth on the periodic table. Bismuth is in group 15 and period 6, with an atomic number of 83.

Key concepts

Atomic Number

The atomic number is a fundamental concept in chemistry, representing the number of protons present in the nucleus of an atom. This number uniquely identifies a chemical element and determines its position on the periodic table. For instance, hydrogen, the simplest element, has an atomic number of 1 because it has one proton in its nucleus.

Atomic numbers increase sequentially as you move from one element to the next on the periodic table. This allows chemists to easily predict certain properties of elements. For example, the atomic number of boron is 5, indicating it has five protons. This also means that in a neutral atom, the number of electrons will be the same as the number of protons.

Understanding the atomic number helps in classifying elements and predicting their chemical behavior. This concept is key in the study of atomic structure and chemistry.

Chemical Elements

Chemical elements are the building blocks of matter, and each is defined by its unique atomic number. An element consists of atoms of a single type, making it a pure substance. These elements are represented on the periodic table by symbols such as H for hydrogen or Al for aluminum.

Elements are organized in the periodic table according to their atomic number, electron configuration, and recurring chemical properties. For example, elements in the same group often display similar chemical reactions. Aluminum, with an atomic number of 13, exhibits properties typical for group 13 elements.

Chemical elements are essential for understanding the composition of the universe and the formation of compounds. They react with each other in various ways, leading to the vast array of substances we encounter.

Groups and Periods

The periodic table is organized in a grid format, consisting of rows called periods and columns known as groups. These arrangements reveal significant information about the elements.

• **Groups**: Vertical columns in the periodic table are known as groups. Elements within the same group share similar chemical properties and valence electron configurations. For example, titanium is found in group 4, which is characterized by elements having a similar oxidation state.
• **Periods**: Horizontal rows are called periods. As you move from left to right within a period, the atomic number increases, indicating more protons in the nucleus and electrons in the outer shells. For instance, arsenic is located in period 4, where elements have progressively filled electron shells.

Groups and periods allow scientists to predict the behavior and reactivity of elements, making these divisions fundamental for studying chemical interactions.