Parts of an atom: Label the diagram Atoms contain 2 parts: The atomic nucleus contains ___________ and ___________ _________ fly around the nucleus near the speed of light

What Atoms are made of Atoms are made of 3 parts. Protons are found in the atomic nucleus. They have a __________electrical charge. Neutrons are also found in the atomic nucleus. They have _____________. Electrons are found outside of the nucleus. They have a ___________charge.

Different Elements = Different Atoms Atoms of different elements are different from one another because they have _______________ of protons, neutrons, and electrons.

Atomic Number The atomic number is the _________________________________ in an atom’s nucleus. In a neutral atom (charge = 0), there are __________ numbers of positive protons and negative electrons. If atoms ______electrons they become negative, and if they ________electrons, they become positive.

What causes atomic bonds? When atoms __________________________________to one another, that is called a chemical reaction. Why do chemical reactions happen?

It’s all about Potential Energy Atoms bond to get a lower energy configuration. Arrows indicate increasing potential energy

But Why? ELECTRONS DETERMINE HOW ATOMS BOND Atoms that have a full outer energy level are very stable. This is the driving force of bonding reactions. Atoms bond together in a way that fills their outermost electron energy level. (2 or 8) This is the lowest energy configuration possible.

Types of Bonds Type of bond What happens Example molecule

Ionic Bonds An atom loses 1 or more valence electrons, giving it a positive charge. Another atom gains the electron(s) and becomes negatively charged + & - ions attract. - + e- e- Cl e- Na e- e- e- e- e-

Covalent bonds 2 atoms share a pair of valence electrons H H e- e-

TWIST: Polar Covalent Bonds In a polar covalent bond, a pair of electrons is shared between two atoms… unevenly One part of the molecule now has a small – charge, and the other has a small + charge Polar covalent Electron Sharing 100% Non-polar covalent 100% Ionic

Recap Atoms are made of positive protons, neutrons with no charge, and negative electrons. The number of protons and electrons determines what charge an atom will have. Chemical reactions occur when atoms change how they are bonded together. Atomic bonds can be ionic, covalent, or polar covalent. Ionic: electron(s) transferred Covalent: pairs of electrons are shared Polar covalent: pairs of electrons are shared unevenly.