Chemistry

Workplace hazardous materials information system used to inform employees and other with the dangers of working with a certain chemical

A physical property is the visible property of a substance which describe its qualities. It includes - color - state - crystal shape - ductility - malleability - boiling point - melting point - solubility - conductivity

These are the properties of a substance which become apparent during a chemical reaction. - reaction to air - reaction to water - reaction to heat - flash point (temp at which chemical burns/sparks) - formation of a precipitate (solid) - formation of a gas

Qualitative is data which is observed, quantitative is data which is measured

Matter is anything that takes up space and has mass. It can be solid, liquid, or gas.

A mixture is a combination of substances. It includes solutions, mechanical mixtures, suspensions, and colloids. It is a combination of matter which cannot be separated by physical means. No definite composition

Solutions are homogenous, mechanical mixtures, suspensions, and colloids are heterogenous. Homogenous substances are those where different components are not visible. The composition is constant throughout the mixture.

An element refers to a singular material on the periodic table (includes things like O3 (same element combined)). It cannot be chemically broken down A compound which is a chemically combined ratio which creates a new substance. It can be separated into elements

1800 - the billiard ball model which states that all matter is made of small particles known as atoms. All atoms have different properties expect those which are the same element. Atoms of different elements combine in specific ratios to form new substances.

1900 - the Plum Pudding Model. - Atoms create identical negative electrons under certain conditions - Atom is a positive sphere with negative electrons embedded into it

1920 - Used alpha particles and the gold foil experiment. Determined that only a few particles bounced back, meaning the atom was mostly empty. Concluded the atom was mostly empty with a small, dense positive core known as the nucleus. Electrons orbitted the core

1930 - Bohr model, which has both protons and neutrons. It also has electrons which orbit the nucleus at a specific energy level. When this level changes, they release color

1940 - Quantum mechanical model - nucleus has nucleons (protons and neutrons). Electron is a cloud and all the electrons function at a specific energy level. These electron orbitals describe the location of electrons

An atom is the smallest part of an element which still has the properties of the element. It contains electrons, protons, and neutrons.

Protons are found in the nucleus of an atom. They compose the majority of the atoms weight. They have a positive charge.

A neutral charge particle found in the nucleus which is the majority of the atoms weight

They have a negative charge, are lightweight, and are found in electron shells orbiting the nucleus. Electrons in energy levels closest to the nucleus have the least energy and are held more tightly in the atom.

The number of protons and electrons in an element.

Rounded mass number - atomic number/protons/electrons

Electron shells determine the amount of electrons on a specific shell level. Electron shells have 2 electrons on the first ring, 8 on the second, 8 on the third, and 18 on the fourth. Valence shells/electrons are the outermost amount of electrons found in an atom. They are determined by period of the group (the AMOUNT of electron shells).

They have the same amount of valence ELECTRONS. They also have similar chemical and physical properties.

Groups are the straight lines and have similar properties. Periods are the number of electron shells in an element.

1 - Alkali metals - very reactive, soft, shiny, silver, reactive, soluble, and very unstable because they only have once valence electron 2 - Alkali earth-metals - shiny, silver, less reactive, two valence electrons 17 - Halogens - poisonous, reactive gasses 18 - Noble Gases - unreactive w/full valence shell

Metals refer to shiny conductive substances. Non-metals are dull insulators. Metalloids have properties of both.