Question

In the periodic table, how many elements are found in each of the following? a. Group 2A b. the oxygen family c. the nickel group d. Group 8A

Short answer

In the periodic table, there are: a. \(6\) elements in Group 2A (alkali earth metals): beryllium, magnesium, calcium, strontium, barium, and radium. b. \(5\) elements in the oxygen family (chalcogens): oxygen, sulfur, selenium, tellurium, and polonium. c. \(3\) elements in the nickel group (transition metals): nickel, palladium, and platinum. d. \(6\) elements in Group 8A (noble gases): helium, neon, argon, krypton, xenon, and radon.

Step-by-step solution

Defining Group 2A

Group 2A elements are also called alkali earth metals. They are found in the second column of the periodic table, and they include the elements beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).

Counting elements in Group 2A

Since there are six elements present in Group 2A: beryllium, magnesium, calcium, strontium, barium, and radium, the answer is six.

Defining the oxygen family

The oxygen family, also known as the chalcogens, is found in Group 6A or Group 16 of the periodic table. The elements in the oxygen family are oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and polonium (Po).

Counting elements in the oxygen family

Since there are five elements present in the oxygen family: oxygen, sulfur, selenium, tellurium, and polonium, the answer is five.

Defining the nickel group

The nickel group is part of the transition metals and is in Group 10 of the periodic table. The elements belonging to the nickel group are nickel (Ni), palladium (Pd), and platinum (Pt).

Counting elements in the nickel group

Since there are three elements present in the nickel group: nickel, palladium, and platinum, the answer is three.

Defining Group 8A

Group 8A elements are also known as noble gases. They are found in the last column of the periodic table and include elements such as helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn).

Counting elements in Group 8A

Since there are six elements present in Group 8A: helium, neon, argon, krypton, xenon, and radon, the answer is six.

Key concepts

Alkali Earth Metals

Alkali earth metals occupy the second column of the periodic table, also known as Group 2A. These elements are characterized by their shiny surface and good conductivity of heat and electricity. They include beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).

Each of these elements has two electrons in their outer shell, which they typically lose, forming +2 ions. This makes them quite reactive, although less so than alkali metals in Group 1A. Due to their reactivity, they are not found freely in nature, but rather in compound forms.

• Beryllium: A lightweight metal used in aerospace materials.
• Magnesium: Known for its importance in biological functions as well as in alloy production.
• Calcium: Essential for bones and teeth, and is found in limestone.
• Strontium, Barium, and Radium: Known for their more specialized uses including fireworks (strontium) and medical procedures (radium).

Chalcogens

The chalcogens, also known as the oxygen family, are located in Group 6A or Group 16 of the periodic table. This group includes oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and polonium (Po).

These elements are diverse in their properties but are generally known for forming -2 ions. They tend to form covalent compounds and play important roles in various processes, such as respiration and sulfur cycles in nature.

• Oxygen: Vital for life, contributes to combustion and forms water through bonding with hydrogen.
• Sulfur: Known for its crystalline forms and uses in fertilizers and chemicals.
• Selenium and Tellurium: Used in electronics and metallurgy, thanks to their photoconductive and thermoelectric properties.
• Polonium: A radioactive metal found in very small amounts and used in nuclear applications.

Transition Metals

Transition metals, including the elements of the nickel group, can be found in the center of the periodic table. The nickel group, specifically, comprises nickel (Ni), palladium (Pd), and platinum (Pt), which are part of Group 10.

These metals are known for their high melting points and ability to form colorful compounds, as well as having multiple oxidation states. They are often good catalysts in chemical reactions.

• Nickel: Utilized in stainless steel and rechargeable batteries.
• Palladium: Important in catalytic converters and hydrogen purification.
• Platinum: Widely used in jewelry, automotive converters, and electronic contacts.

Noble Gases

Noble gases occupy Group 8A, located at the far right of the periodic table. This group includes helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn).

These elements are characterized by a full valence shell, making them extremely stable and generally unreactive. They are monoatomic gases at room temperature and are used for their inert properties.

• Helium: Often used in balloons and as a protective gas in welding.
• Neon: Employed in neon signs, thanks to its vibrant glow when electrified.
• Argon: Commonly used in lighting and as a shielding gas in arc welding.
• Krypton and Xenon: Utilized in high-performance lighting and lasers.
• Radon: A radioactive gas, potentially arising as a health concern in building environments.