What if anything can you tell me about the Periodic Table of Elements? Starter What if anything can you tell me about the Periodic Table of Elements?

Atoms

Notes Atoms are the building blocks of life. Atoms are mostly empty space. The three parts of an atom are electrons, protons, neutrons Most of the mass of an atom is in the nucleus. The nucleus is made of protons and neutrons. The electrons circle the nucleus Neutrons and protons have the same mass.

The number of neutrons is equal to the number of protons. Electrons have a negative charge and protons have a positive charge. In molecules, the atoms are held together by bonds. Only the electrons farthest from the nucleus form bonds. We use chemical symbols instead of the names of atoms. Longer molecules are called polymers. If the atoms in a molecule of a material are the same, the material is an element. If the atoms in the molecules of a material are different, the material is a compound.

On the periodic table of elements, the number in the squares are called atomic numbers. The atomic number is equal to the number of protons in the nucleus of each atom of that element. The atomic number is equal to the number of electrons. Each up-and-down row is called a group. The elements in group 18 have a full set of outer electrons. These elements almost never form compounds with anything. They are the inert gases. Elements in the top rows are more reactive than elements in lower rows. There are metals and nonmetals.

Common metals iron (Fe), gold (Au), silver (Ag), platinum (Pt), chromium “chrome” (Cr), copper (Cu), nickel (Ni) lead (Pb), tin (Sn) Bromine (Br) is a nonmetal that is a liquid Nitrogen (N), oxygen (O), fluorine (F), and chlorine (Cl) are gases and the others are all solids. Carbon (C) is in almost all important compounds. Compounds containing carbon are called organic compounds. Many organic compounds contain hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), and sulfur (S) Hydrogen behaves like a nonmetal. Carbon can take on three forms: coal, graphite, and a diamond

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