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Nomenclature and Identity Element list: Period 3 includes sodium (Na), magnesium (Mg), aluminium (Al), silicon (Si), phosphorus (P), sulfur (S), chlorine (Cl), and argon (Ar). Element list: Period 3 of the periodic table contains eight elements: sodium (Na), magnesium (Mg), aluminium (Al), silicon (Si), phosphorus (P), sulfur (S), chlorine (Cl), and argon (Ar). These elements … Read more

Early Contributions Lavoisier’s role: He helped form the initial understanding of chemical elements. Lavoisier’s role: Antoine Lavoisier was one of the first scientists to carefully study and classify substances. He grouped them into elements and compounds, helping others understand that some materials cannot be broken down further. This work laid the foundation for the concept … Read more

Ordering Principle Atomic number order: Elements are organized by increasing atomic number, which equals the number of protons in the nucleus. Atomic number order: In the modern periodic table, the elements are arranged in a sequence that increases by atomic number. The atomic number is the number of protons found in the nucleus of each … Read more

Nomenclature and Identity Noble gas names: Group 18 elements are referred to as noble gases or inert gases. Noble gas names: The elements in Group 18 are commonly called noble gases because they do not easily react with other substances. They are also called inert gases because they tend to stay unchanged in chemical reactions … Read more

The Mole (mol) Definition of mole: The mole is the SI unit for the amount of substance, defined by the number of particles in 12 grams of carbon-12. Definition of mole: The mole is a special unit in science used to measure the amount of a substance. It is part of the International System of … Read more

Chemical Formulae Definition of chemical formula: A chemical formula uses symbols and subscripts to represent the composition of a substance. Definition of chemical formula: A chemical formula is a short and easy way to show what elements are in a substance and how many atoms of each element it contains. Instead of writing a full … Read more

Chemical Equations Definition of chemical equation: A chemical equation represents a chemical reaction using formulas and symbols for reactants and products. Definition of chemical equation: A chemical equation is a short and clear way to show a chemical reaction. It uses chemical formulas and symbols to show what substances are reacting and what new substances … Read more

Relative Atomic Mass (RAM) Definition of RAM: RAM is the mass of an atom compared to 1/12 the mass of a carbon-12 atom. Definition of RAM: Relative Atomic Mass (RAM) tells us how heavy an atom is when we compare it to something called the carbon-12 atom. Scientists chose carbon-12 as a standard because it … Read more

Protons Symbol: Protons are represented by the symbol ‘p’. Symbol: Protons are represented by the symbol ‘p’. Scientists use this short form to refer to protons quickly when writing equations or drawing diagrams. It’s like using initials to save space and make things simpler. Charge: They carry a positive charge of +1. Charge: Protons carry … Read more

Isotopes Definition of isotopes: Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons. Definition of isotopes: Isotopes are different versions of the same type of atom. Even though they all belong to the same element (like all being types of carbon or hydrogen), they don’t have … Read more