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Updated Mar 22, 2026

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Understanding the First 20 Elements - Higher Chemistry Notes

Sophieeee 🎀👝🛍🌺💓

@sophiesnotes

The first 20 elements in the periodic table aren't just... Show more

# PERIODICITY
THE FIRST 20 ELEMENTS

All the chemical elements are arranged in the periodic table in
horizontal rows (periods) in order of i

Understanding Periodic Table Organisation and Covalent Molecular Elements

The periodic table arranges elements in horizontal rows (periods) by increasing atomic number and vertical columns (groups) by similar properties. Elements in the same group behave similarly because they have the same number of outer electrons, making it dead easy to predict how they'll react.

Covalent molecular structures are made up of separate molecules held together by weak intermolecular forces. The actual covalent bonds form when non-metal atoms share electrons to achieve a stable outer electron arrangement (like noble gases). Think of it as atoms "holding hands" with shared electrons.

Most covalent molecular elements are diatomic (two atoms joined together): hydrogen (H₂), nitrogen (N₂), oxygen (O₂), fluorine (F₂), and chlorine (Cl₂). Some elements form larger molecules like phosphorus (P₄) and sulfur (S₈).

Quick Tip: Covalent molecular elements have low melting points, low densities, and don't conduct electricity because there are no free-moving charged particles.

Network, Metallic, and Monatomic Structures

Covalent network structures are completely different beasts - they're giant lattices where atoms are connected by strong covalent bonds throughout the entire structure. Boron, carbon, and silicon form these networks, resulting in incredibly high melting points because you'd need to break loads of strong bonds to melt them.

Metallic structures consist of positive metal ions surrounded by a "sea" of delocalised electrons. The metals lithium, beryllium, sodium, magnesium, aluminium, and calcium all have this structure. These free-moving electrons make metals excellent electrical conductors - it's like having a motorway for electric current.

Monatomic structures are the loners of chemistry - individual atoms held together only by weak intermolecular forces. The noble gases (helium, neon, argon) exist this way because they already have full outer electron shells, so they don't bother forming bonds with other atoms.

Remember: The stronger the bonds holding a structure together, the higher its melting point will be. Network > metallic > molecular > monatomic.

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Chemistry

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Updated Mar 22, 2026

•

2 pages

Understanding the First 20 Elements - Higher Chemistry Notes

Sophieeee 🎀👝🛍🌺💓

@sophiesnotes

The first 20 elements in the periodic table aren't just randomly arranged - they're organised by atomic number and grouped by similar properties. Understanding how these elements bond and structure themselves is crucial for predicting their behaviour and properties.

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Understanding Periodic Table Organisation and Covalent Molecular Elements

Quick Tip: Covalent molecular elements have low melting points, low densities, and don't conduct electricity because there are no free-moving charged particles.

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Network, Metallic, and Monatomic Structures

Remember: The stronger the bonds holding a structure together, the higher its melting point will be. Network > metallic > molecular > monatomic.