What are isotopes. Do Now: What is the smallest part of matter What are isotopes? Do Now: What is the smallest part of matter? HW: Circulatory system worksheet  

Matter is anything that has volume and mass. Atoms Matter is anything that has volume and mass. An element is a substance that cannot be broken down into simpler substances by physical or chemical means. Copyright © McGraw-Hill Education Matter

An electron has little mass, but it has a negative electric charge Atoms. The center of an atom is called the nucleus, which is made up of protons and neutrons. A proton is a tiny particle that has mass and a positive electric charge. A neutron is a tiny particle with approximately the same mass as a proton, but it has no electrical charge. An electron has little mass, but it has a negative electric charge Matter Copyright © McGraw-Hill Education

The number of protons in an atom’s nucleus is its atomic number. Mass number The number of protons in an atom’s nucleus is its atomic number. The sum of the protons and the neutrons in an atom’s nucleus is its mass number. Matter Copyright © McGraw-Hill Education

Isotopes Radioactive isotopes Atoms of the same element that have different mass numbers are called isotopes. Radioactive decay is the spontaneous process through which unstable nuclei emit radiation. In the process of radioactive decay, a nucleus can lose protons and neutrons, change a proton to a neutron, or change a neutron to a proton. Matter Copyright © McGraw-Hill Education

What elements are most abundant? The two most abundant elements in the universe are hydrogen and helium. However, the two most abundant elements in Earth’s crust are oxygen and silicon. Matter Copyright © McGraw-Hill Education

Covalent Bonds A chemical bond is the force that holds together the elements in a compound. The attraction of two atoms for a shared pair of electrons that holds the atoms together is a covalent bond. Combining Matter Copyright © McGraw-Hill Education

Covalent Bonds Polar molecules A polar molecule has a slightly positive end and a slightly negative end. Combining Matter Copyright © McGraw-Hill Education

Ionic Bonds An ionic bond is the attractive force between two ions of opposite charge. Combining Matter Copyright © McGraw-Hill Education

Metallic Bonding In a metallic bond, the positive ions of the metal are held together by the attraction to the negative electrons moving among them. Combining Matter Copyright © McGraw-Hill Education

Mixtures and Solutions A mixture is a combination of two or more components that retain their identities. When a mixture’s components are easily recognizable, it is called a heterogeneous mixture. In a homogeneous mixture, also called a solution, the component particles cannot be distinguished, even though they still retain their original properties. A solution can be liquid, gaseous, or solid. Combining Matter Copyright © McGraw-Hill Education

Mixtures and Solutions Acids An acid is a solution containing a substance that produces hydrogen ions (H+) in water. The pH scale is based on the amount of hydrogen ions in a solution. Bases When a solution produces hydroxide ions (OH–) in water, the solution is called a base. Combining Matter Copyright © McGraw-Hill Education

hot, highly ionized, electrically conducting gases called plasmas Solids Solids are substances with densely packed particles, which can be ions, atoms, or molecules. Most solids are crystalline structures, giving solids definite shape and volume. Liquids the particles can slide past each other, and the substance becomes liquid. Liquids take the shape of the container they are placed in, but they do have a definite volume. Gases This process of change from a liquid to a gas at temperatures below the boiling point is called evaporation. Gases, like liquids, have no definite shape. Gases also have no definite volume unless they are restrained by a container Plasma hot, highly ionized, electrically conducting gases called plasmas Copyright © McGraw-Hill Education

States of Matter Copyright © McGraw-Hill Education