1.1. Describe the structure of the chemical elements: • hydrogen • carbon • oxygen • nitrogen.

This guide will help you answer 1.1. Describe the structure of the chemical elements: • hydrogen • carbon • oxygen • nitrogen.

Understanding the structure of fundamental chemical elements like hydrogen, carbon, oxygen, and nitrogen is vital in health and social care, as these elements play a significant role in biological processes.

Hydrogen

Hydrogen is the simplest and most abundant element in the universe. It is represented by the symbol H and has an atomic number of 1, which means it contains one proton in its nucleus.

Atomic Structure

• Protons: 1
• Neutrons: Usually 0. The most common form of hydrogen, known as protium, has no neutrons. However, other forms (isotopes) of hydrogen, like deuterium, have one neutron.
• Electrons: 1, which orbits the nucleus.

Its single electron is found in the first energy level, closest to the nucleus. Since this level can hold a maximum of two electrons, hydrogen often reacts with other elements to share or exchange electrons, forming chemical bonds.

Role in Biology

Hydrogen is an essential component of water and organic molecules. It participates in energy transfer processes, such as cellular respiration, through molecules like ATP (adenosine triphosphate).

Carbon

Carbon, represented by the symbol C, has an atomic number of 6. It is the backbone of all organic compounds, making life on Earth possible.

Atomic Structure

• Protons: 6
• Neutrons: 6 (for the most common isotope, carbon-12).
• Electrons: 6, arranged in two energy levels:
• 2 electrons in the first shell.
• 4 electrons in the second shell.

Carbon has four electrons in its valence (outermost) shell, which allows it to form four chemical bonds with other atoms. This unique property gives carbon the ability to create long chains and complex structures necessary for DNA, proteins, carbohydrates, and lipids.

Role in Biology

Carbon is the foundation of biomolecules. It is present in:

• Sugars, for energy storage and structure.
• Proteins, which are crucial for cell functioning.
• Nucleic acids, like DNA and RNA, which carry genetic information.

Oxygen

Oxygen is a highly reactive element with the symbol O and atomic number 8. It is crucial for the survival of most living organisms.

Atomic Structure

• Protons: 8
• Neutrons: 8 (in the most common isotope, oxygen-16).
• Electrons: 8, distributed across two shells:
• 2 electrons in the first shell.
• 6 electrons in the second shell.

The six electrons in its valence shell make oxygen highly electronegative, meaning it readily attracts electrons from other elements. This property is key to its role in forming compounds like water (H₂O) and in biochemical reactions.

Role in Biology

• Oxygen is required for the process of cellular respiration, where glucose and oxygen are converted into energy (ATP).
• It is a component of water and many other molecules in the body.
• Oxygen transport to tissues is facilitated by haemoglobin in red blood cells.

Nitrogen

Nitrogen is represented by the symbol N and has an atomic number of 7. It makes up about 78% of the Earth’s atmosphere and is an essential element in proteins and nucleic acids.

Atomic Structure

• Protons: 7
• Neutrons: 7 (for the most common isotope, nitrogen-14).
• Electrons: 7, distributed in two energy levels:
• 2 electrons in the first shell.
• 5 electrons in the second shell.

Nitrogen has five electrons in its valence shell, so it often forms three covalent bonds with other atoms to complete its octet (8 electrons in the outer shell). This ability to form multiple bonds makes nitrogen versatile in creating complex molecules.

Role in Biology

• Nitrogen is a major component of amino acids, the building blocks of proteins.
• It is found in nucleotides, which are part of DNA and RNA, essential for genetic information.
• It is involved in the nitrogen cycle, a process essential for life, where nitrogen is converted into forms that plants and animals can use.

Comparing the Structures

All four elements have unique atomic structures that determine their chemical behaviours:

• Hydrogen has one proton and one electron, making it the simplest element.
• Carbon has four valence electrons, allowing it to form long chains and complex biomolecules.
• Oxygen is highly electronegative, enabling its role in reactions like combustion and respiration.
• Nitrogen can form triple bonds, making it crucial for protein and nucleic acid formation.

Their roles in biology hinge on these structural differences. Together, hydrogen, carbon, oxygen, and nitrogen make up the majority of the human body’s mass, demonstrating their importance in sustaining life.