Problem 2 - A Complete Resource Book in Chemistry for JEE Main

Question

An element having atomic number 56 belongs to (a) lanthanides (b) actinides (c) alkaline earth metals (d) none of these

Step-by-Step Solution

Answer

The element with atomic number 56 belongs to alkaline earth metals (choice c).

Step 1: Identify Atomic Number

The atomic number given in the problem is 56. This is the unique identifier for an element and helps determine its properties and position in the periodic table.

Step 2: Locate Element on the Periodic Table

Find which element corresponds to the atomic number 56 on the periodic table. Reviewing the table, atomic number 56 corresponds to the element Barium (Ba).

Step 3: Determine the Element's Family

Identify the group or family to which the element Barium belongs. Barium is located in Group 2 of the periodic table, which is known as the alkaline earth metals.

Step 4: Match with Options

Review the given answer choices and match them to the family you identified for Barium. The correct family for Barium is alkaline earth metals.

Key Concepts

Atomic Number

In the world of chemistry, each element is distinguished by its atomic number. It is an integral part of the periodic table's design and provides crucial insights into the characteristics of an element. The atomic number is defined as the number of protons in the nucleus of an atom and it determines the element's identity.

This means that if you know the atomic number, you can easily pinpoint the element on the periodic table. For instance, with an atomic number of 56, we can quickly identify the element as barium. The atomic number not only helps in identifying an element but also gives an understanding of its chemical properties and where it appears in the periodic sequence.

In chemical notation, the atomic number is usually written above the element's symbol on the periodic table. For barium, you will find the number 56 placed above the symbol 'Ba'. This system allows scientists and students alike to efficiently navigate the vast array of elements in the periodic table.

Alkaline Earth Metals

Alkaline earth metals are an essential group in the chemical element classification. Situated in Group 2 of the periodic table, these metals include beryllium, magnesium, calcium, strontium, barium, and radium. This family plays a significant role in various scientific and industrial applications due to their unique properties.

Here are some key characteristics of alkaline earth metals:

• They have two electrons in their outer shell.
• These metals are shiny and silvery-white.
• They are relatively more resistant to heat compared to alkali metals.
• When reacting with water, they form alkaline solutions and release hydrogen gas.
• They are good conductors of electricity.

Alkaline earth metals are not found freely in nature due to their reactivity. Instead, they are typically found in compound forms, such as calcium in limestone and barium in barium sulfate. The properties shared by these metals contribute greatly to their utility in fields such as metallurgy, medicine, and electronics.

Barium

Barium is a fascinating element sitting snugly in the alkaline earth metals group, noted for its chemical symbol 'Ba' and atomic number 56. It is notable for several distinctive features and uses that make it stand out.

Barium is a soft, silvery metal appearing in the earth's crust primarily as barium sulfate or barium carbonate. Though highly reactive, it serves critical functions in various industries:

• In the medical field, barium sulfate is used in diagnostic imaging of the stomach and intestines because it is opaque to X-rays.
• Barium compounds are often used in fireworks to create green colors.
• It is also utilized in the manufacturing of glass and ceramics.

When working with barium, caution is required due to its reactivity and potential toxicity, particularly in its soluble compound forms. Nevertheless, its vibrant applications and contributions to technology and medicine make it an essential element worth studying.