Atoms & Molecules Created by: Mrs. Dube

Structure of Atoms Atoms are composed of three types of particles: protons, neutrons, and electrons. (copy into notes)

Inside the Atom! Nucleus is the central region of an atom where most of the atom’s mass is found in protons and neutrons. A proton is a positively charged particle found in the nucleus of the atom. A neutron is an uncharged particle, also found in the nucleus of the atom. (copy all bullets into notes)

Outside the Nucleus Electrons are negatively charged particles that move around outside the nucleus. (copy into notes)

Quick Question! Explain the structure of the atom including the parts and their location. (answer in notes)

Pure Substances Matter can be pure or it can be two or more substances mixed together. (copy into notes) A pure substance has only one type of component; for example, pure water contains only water molecules. (copy into notes) Pure water, pure sugar, and pure baking soda!

Mixed Substances A mixture is a combination of different substances that remain the same individual substances and can be separated by physical means. (copy into notes) Example of a mixture: fruit salad containing apples, oranges, bananas, and strawberries. You can pick out the apples from the mixture or any other fruit by pulling it out of the bowl!

Quickie Quiz! What is the difference between a mixture and a pure substance? How are mixtures separated? Give an example of a mixture from your daily life! Answer both questions in notes.

Elements An element is a substance that contains only a single type of atom. (copy into notes) The number of atoms is not important as long as all of the atoms are of the same type. (copy into notes) You CANNOT separate an element into other substance. There are more than 100 elements! (copy into notes)

Molecules When two or more atoms bond together, or combine chemically, they make a particle called a molecule. (copy into notes) A molecule is a group of atoms held together by a specific type of chemical bond so that they move together as a single unit. (copy into notes) Molecules can be made up of the same type of atoms or different types of atoms. (copy into notes)

Types of Molecules A water molecule has 2 hydrogen atoms and 1 oxygen atoms (copy into notes) A hydrogen gas molecule has 2 hydrogen atoms bonded together (copy into notes) An oxygen gas molecule has 2 oxygen atoms bonded together (copy into notes)

Compounds (copy all bullets) A compound is a substance that consists of two or more different types of atoms that are bonded together. A compound can have very different properties from the individual elements that make up the compound! Compounds are separated by breaking the bonds between the elements and CANNOT be separated by physical means.

Quiz Time! (Answer in notes) How are molecules formed? How do you separate molecules? How do you separate elements? How are compounds separated?

Characteristic Properties Physical properties describe a substance! Physical properties are the characteristics of a substance that can be observed without changing the identity of the substance. All of your senses can be used to detect physical properties.

Physical Properties (copy all) Color Shape Size Texture Volume Mass Density Boiling point Melting point Freezing point Solubility

Physical Properties Physical properties of a substance are independent of the amount of the sample. (copy into notes) For example, the boiling point of water is 212°F or 100°C whether you have a gallon of water or a cup of water. Density of lead will always be 11,300 kg/m3 and the density of gold will always be 19,300 kg/m3

Quick Quiz! Select a substance from your daily life and name four characteristic properties of the substance you selected. Answer in notes!