Bonds Atoms of different elements may join together in a number of ways.
Colors First, take two primary colors, like elements of color instead of matter. Then, we combine them… And we get a new color, totally unlike the first two…
Elements Now, take two elements of matter: sodium and chlorine. So if we combine these two, we should get a new substance with different properties. Sodium chloride is formed, a compound with new properties
Atomic Model Reminders Cl 17 35.453 To form this bond, an electron is lost by sodium, and picked up by chlorine. Making two charged particles. Each ion has a fill valence orbital. Since one ion is negatively charged (cation) and one is positively charged (anion), they attract each other. They form a bond, and since they are both ions, it is called an ionic bond. Na + Cl - 11p + 12n 0 2e - 8e - 1e - Na 11 22.9898 17p + 18n 0 2e - 8e - 7e - 8e - Each atom now has a different number of electrons and forms an ion.
Ionic Bonds Compounds formed from ionic bonds tend to have a few things in common: – They are grids of regularly arranged ions. Sodium Chloride (Na + Cl - )
Ionic Bonds Compounds formed from ionic bonds tend to have a few things in common: – They are grids of regularly arranged ions. – The grid gives them a crystal shape.
Ionic Bonds Compounds formed from ionic bonds tend to have a few things in common: – They are grids of regularly arranged ions. – The grid gives them a crystal shape. – They also have high melting points.
Sharing Electrons Sometimes, two atoms can share up to three electrons. When electrons are shared it is called a covalent bond. Covalent= co(shared) + valence (outer orbital)
Hydrogen 1p + 1p + e - e - Here are two hydrogen atoms, both looking for filled valence energy levels. How many e - do they need? Neither positive charge is strong enough to remove an electron, so instead they share... Now each electron is part of both atoms, so each atom has two electrons in it’s valence shell, but overall, the group remains neutral. 2e -
Oxygen Here are two oxygen atoms, both looking for filled valence energy levels. How many e - do they need? 8p + 8n 0 8p + 8n 0 2e - 6e - 2e - 6e - So each atom will share two electrons with the other one. 2e - 4e - 4e - 4e - How many valence electrons does each atom have? How many total shared electrons are there?
Covalent Compounds: Molecules This new particle made of two or more atoms covalently bonded together is called a molecule. A molecule is the smallest particle of a compound that retains all the properties of the compound.
Water 1p + 8p + 8n 0 1e - 2e - 6e - 1e - 4e - 2e -