Periodic Table

The periodic table is a tabular arrangement of the chemical elements, organized by their atomic number, electron configuration, and recurring chemical properties.

Structure of the Periodic Table

The periodic table is organized into periods (rows) and groups (columns). The elements are arranged in order of increasing atomic number, which reflects the number of protons in an atom's nucleus.

Periods

There are 7 periods in the periodic table. Each period represents the energy level or shell in which the electrons are located.

Groups

There are 18 groups in the periodic table. Elements in the same group have similar chemical properties due to the same number of valence electrons.

Key Information for Each Element

For each element, the periodic table provides key information such as the element's symbol, atomic number, atomic mass, and electron configuration.

Study Tips

Memorize the first 20 elements and their symbols.
Understand the trends in the periodic table, such as atomic radius, electronegativity, and ionization energy.
Practice using the periodic table to predict chemical properties and reactions.

◂Science Worksheets and Study Guides Second Grade. What is science?

Vocabulary/Answer key

What is science?

The resources above cover the following skills:

LIFE SCIENCE

Ecosystems: Interactions, Energy, and Dynamics

Obtain information from literature and other media to illustrate that there are many different kinds of living things and that they exist in different places on land and in water (e.g., woodland, tundra, desert, rainforest, ocean, river).

EARTH AND SPACE SCIENCE

Earth’s Systems

Make observations from media to obtain information about Earth’s events that happen over a short period of time (e.g., tornados, volcanic explosions, earthquakes) or over a time period longer than one can observe (e.g., erosion of rocks, melting of glaciers).

Collect and evaluate data to identify water found on Earth and determine whether it is a solid or a liquid (e.g., glaciers as solid forms of water; oceans, lakes, rivers, streams as liquid forms of water).