Question

An atom of an element contains 66 electrons. Which element is it?

Short answer

The element with an atom containing 66 electrons is Dysprosium (Dy).

Step-by-step solution

Recall that atomic number is equal to the number of electrons

The atomic number of an element indicates how many protons it has in its nucleus. Since atoms are neutral, the number of protons is equal to the number of electrons. Therefore, the atomic number is also equal to the number of electrons in an atom.

Find the element with atomic number 66

Consult the Periodic Table of Elements to find the element with an atomic number of 66. In this case, you will find that the element with atomic number 66 is Dysprosium (Dy).

State the element

The element with an atom containing 66 electrons is Dysprosium (Dy).

Key concepts

Atoms

Atoms are the basic building blocks of matter. They form the structure of all elements and are composed of three primary particles: protons, neutrons, and electrons.
Protons are positively charged particles found in the nucleus, while neutrons carry no charge and also reside in the nucleus alongside protons. Electrons are negatively charged particles that orbit the nucleus in shells or energy levels.
Some key points about atoms include:

• The nucleus is dense and contains most of the atom’s mass due to protons and neutrons.
• Electrons inhabit energy levels around the nucleus.
• An atom remains neutral when the number of electrons equals the number of protons.
• The number of protons (atomic number) defines the specific element.

Periodic Table

The Periodic Table is a comprehensive chart where all chemical elements are organized based on their atomic number, electronic configuration, and recurring chemical properties.
Each element's position on the table reveals much about its chemical behavior. Some important features of the Periodic Table:

• Elements are listed in order of increasing atomic number from left to right and top to bottom.
• Vertical columns are called groups or families, and elements in a group often have similar properties.
• Horizontal rows are known as periods, and elements in a period show a progression of properties.
• The table is divided into metals, non-metals, and metalloids based on specific characteristics.

The Periodic Table is an invaluable tool for predicting the properties and behaviors of elements in different chemical reactions.

Electrons

Electrons are one of the fundamental particles that make up an atom. These tiny particles carry a negative electrical charge and orbit the nucleus in various energy levels or shells. Their arrangement plays a pivotal role in chemical reactions and the formation of compounds.
Key points about electrons include:

• They determine the chemical properties and reactivity of an element.
• Electrons fill energy levels in a defined order, known as electron configuration.
• The outermost electrons, or valence electrons, are crucial in bonding with other elements.
• An atom becomes an ion when it gains or loses electrons.

Understanding electrons is essential for grasping how elements interact and form new substances in the vast field of chemistry.