Matter

Matter

• Matter makes up the universe, takes up space, and has mass.
• Matter consists of atoms that form elements.
• Elements combine into large groups to create the physical world.
• The total mass of the universe is conserved, meaning it can't be created or destroyed, only transformed.

Composition of Matter

• Matter is made of small particles with elements as the simplest form, consisting of smaller particles called atoms.

Structure of Atoms

• Atoms consist of protons, neutrons and electrons; protons and neutrons make up the nucleus; electrons form a cloud around the nucleus.
• Matter has an equal number of electrons and protons in its balanced state.
• Electromagnetic, strong, and weak forces keep atoms together.

Nucleus

• Protons and neutrons are the heaviest parts of the atom and make up most of its mass.
• The balance between protons and neutrons varies among elements with larger atoms having more neutrons.
• Protons have a positive charge, yet the nucleus doesn’t fly apart due to neutrons producing a strong force to overcome repulsion.

Electrons

• Electrons have a negative charge and spin rapidly around the nucleus, resulting in the appearance of a cloud.
• An electron's mass is almost 1000 times smaller than a proton's and isn't counted in an atom's mass.
• The attraction between the positive protons in the nucleus and the negative orbiting electrons binds the electron to its nucleus.
• Electrons produce magnetic fields as they spin and move, contributing to the electromagnetic force.
• Most of an atom's volume is empty space.

Fundamental Forces

• Four fundamental forces in increasing strength: gravity (insignificant on atomic scale), weak nuclear force (radioactivity), electromagnetic force (electrical/magnetic energy), and strong nuclear force (holds nuclei together).

Elements

• Chemical elements can't be broken down by ordinary processes, making them fundamental materials of matter with 118 known elements.
• Pure copper, for example, comprised of only copper atoms (Cu), is an element, and an atom is the smallest part retaining the properties of its element.

Hydrogen and Helium Atoms

• The electrical properties of an element are determined by how full the outer shell is.
• Electron shells/orbits are regions where electrons are found, numbered 1, 2, 3 etc. or K, L, M etc., with K closest to the nucleus.
• The maximum number of electrons possible in each shell = 2n^2; outer/valence shells can never have > 8 electrons.

Periodic Table of Elements

• Each atom is identified by its number of protons, neutrons, and electrons.
• The atomic number determines the chemical element.
• Mass number sums protons and neutrons in the nucleus.
• The positions of the elements provides information about arrangement of electrons
• Atoms must be electrically neutral with the number of electrons equaling number of protons.

Periodic Table Blocks

• The atomic number is at the top of the block and represents the number of protons in an element's atom.
• The chemical symbol is an abbreviation of the element's name.
• The relative atomic mass is an average mass of the element's atoms.

Bonding

• Atoms arrange into stable patterns to fill valence shells.
• Chemical bonds hold atoms together in molecules categorized Covalent (Electron Sharing) and Ionic (Electron Transfer).

Covalent Bonding

• Covalent bonds share electrons between atoms so that the atoms get a total of eight electrons.
• Shared electrons form an orbit around both nucleuses, producing a molecule.
• Covalent bonding involves the sharing of valence electrons.

Ionic Bonding

• Ionic bonds transfer valence electrons, resulting in one atom with positive (+) charge and one with negative (-) charge.
• Unlike charges attract, bonding the atoms together.
• Table Salt (NaCl) is an example.

Ions

• Ions are formed when atoms lose or gain electrons during bonding resulting in positively charged ions (cations) and negatively charged ions (anions).

Isotopes

• Isotopes: atoms of an element w/ different mass numbers caused by different numbers of neutrons.

Molecules

• Molecules consist of any bonded combination of atoms.
• Compound molecules comprise multiple elements with at least 2 different types of atoms in a fixed ratio, like H20.
• All compounds are molecules, but not all molecules are compounds.
• Water contains H2O molecules.

Structure of Molecules

• A molecule can consist of 2 atoms of the same element (ex. oxygen - O2), or atoms of different elements (ex. water - H2O).

Chemical Compounds

• Compounds contain identical molecules, with each comprised of different atoms in specific proportions, forming separate substances with different characteristics from their original.

Mixtures

• Mixtures contain two or more substances that retain individual characteristics without chemical combination.
• Mixtures contain varying ingredient ratios without a fixed chemical compound.
• Air and metal alloys are further examples of mixtures.
• Alloys can have microscopically changed characteristics.

States of Matter

• Atoms/molecules are always in motion & internal kinetic energy (KE) determines physical state, known as heat corresponding to molecular activity.
• The physical state does not affect chemical structure
• Heat impacts matter, changing chemical makeup or properties.
• Ice, water and steam are all H2O molecules, but with different levels of energy.
• The four natural states of matter are solid, liquid, gas, and plasma.

Definitions of Changes in State of Matter

• Condensation: Gas to liquid (cooling).
• Evaporation: Liquid to gas (heating).
• Sublimation: Solid to gas (heating).
• Deposition: Gas to solid (cooling).
• Melting: Solid to liquid (heating).
• Freezing: Liquid to solid (cooling).
• Changes occur and surrounding pressure affects the temperature at which changes occur.

Physical States

• Solids: Molecules are arranged with regular and repeating patterns, held firmly, but vibrate with low kinetic energy.
• Liquids: Molecules flow easily but are bound with attractive forces assuming the containers shape.
• Gases: Molecules fly in varied directions at great speeds where attractive forces are insignificant.
• Plasma: Atoms lose electrons, becoming a conductive mixture of electrons and nuclei.

Liquids

• Liquids result from adding heat to solids, thus allowing molecules to loosen bond and take the shape of their container.
• Liquids are mostly incompressible.
• Surface tension is bonding force that prevents liquids from expanding.

Gases

• Further heat increases molecular movement until surface tension is overcome; atoms becoming vapors with lots of space and heat.
• Gases have no set shape or volume
• Gases can be compressed by reducing container volume, reducing space between particles.

Flow and Fluids

• Flow indicates the property allows liquids and gases to adopt the shape of their containers, continually deforming depending on pressure.

Plasma

• Plasma forms when significant heat or electricity break electrons away, resulting in charged ions with no shape or volume, and causes electrical conductivity.

Altitude and Matter

• Boiling point of water/liquids corresponds to atmospheric pressure and the vapor rises or floats.
• Pressure drops as you gain elevation, resulting in a decrease in required temperature needed to evaporate.