Matter Unit

Electric Charge

Fundamental property of matter which can be positive or negative

Elementary Charge

Smallest unit of charge, represented by ‘e’

Like Charges… (e.g. positive and positive)

Repel eachother

Opposite Charges… (e.g. positive and negative)

Attract eachother

Electron

Negatively charged particle, outside of nucleus, in electron cloud, opposite of proton

Proton

Positively charged particle, within nucleus, opposite of electron

Neutron

Zero/not charged particle, within nucleus

Nucleus

Core of atom containing protons and neutrons

Unit: amu or Dalton

Proton and Neutron: 1 amu

Electron: 1/2000 amu

Part of an atom with the most mass

Nucleus, due to protons and neutrons

Relative masses

Proton and Neutron: 1,836 g

Electron: 1 g

Which particles occupy the most space in an atom

Electrons

The space inside an atom is mostly…

Empty

The force that keeps electrons orbiting around the nucleus is…

Kinetic energy (momentum), attractive force between protons (+) and electrons (-)

Forces: Weakest to Strongest

Gravity, Weak force, Electromagnetic force, Strong Nuclear force (GWES)

Function of Strong Nuclear Force

Strongest known force of matter, attracts protons and neutrons to each other to keep the nucleus together

Atomic Number

Number of protons in the nucleus, determines an element's identity

Mass Number

Number of protons and neutrons combined

Complete atom

Equal number of protons and electrons

The net charge of a complete atom is…

Zero, the protons and electrons cancel

How do like (same) and opposite charges interact?

Like (same) charges repel from each other,

Opposite charges attract to each other

An ion is…

An atom with a different number of protons and electrons

Positive Ion

More protons than electrons in an atom

Negative Ion

More electrons than protons in an atom

An isotope is…

An atom of the same element (e.g. Oxygen) with a different number of neutrons

Oxygen Isotope example

8 protons 8 neutrons Oxygen atom V.S.

8 protons 9 neutrons Oxygen atom

Matter

Anything with mass which takes up space, made of tiny particles (atoms)

Brownian motion

Irregular or jerky movement caused by particles

Element

Pure substance which cannot be broken down by physical or chemical means, chemically joined, same composition

Atom

Smallest particle of an element retaining the element chemical identity

Molecule

Group of 2+ atoms joined by chemical bonds, can be same or different elements

Compound

Substance containing 2 different elements

Mixture

Combination of different compounds, not chemically bonded

Pure substance

Chemically bonded, cannot be separated into different matter by physical means,

Homogenous Mixture

Same substance throughout

Heterogeneous Mixture

Different samples, not the same proportions of matter

Atoms and molecules in a solid…

Closely packed— hold their shape

Physical properties

Characteristics that can be directly observed

Physical property examples

Color, odor, texture, density, brittleness, state

Physical change

Any change in the size, shape, or phase of matter in which the identity of a substance does not change

Chemical properties

Characteristics that can only be observed when a substance changes

Chemical change

Any change that transforms a substance into a new one (new identity)

Crystalline

Orderly, repeating arrangement of atoms/molecules

Amorphous

Random arrangement of atoms/molecules

Crystalline examples

Salts, minerals, metals

Amorphous examples

Rubber, wax, glass, plastic

Strength

Ability to maintain shape under force

Tensile strength

How much tension a material can withstand before breaking

Hardness

A solid’s resistance to scratching

Elasticity

Ability to be stretched/compressed— then return to original shape

Brittleness

Tendency to crack or break

Ductility

Ability to bend without breaking (steel fork, copper wire)

Malleability

Ability to be pounded into thin sheets (aluminum foil, beverage can)

Thermal expansion

When temperature increases— kinetic energy in atom vibration causes molecule size to increase

Viscosity

Measure of fluids resistance to flow (Higher viscosity: slower flow)

How does size and shape of particles affect viscosity

Large and bumpy particles cause friction, meaning higher viscosity and slower pour

When temperature increase, Viscosity…

Decreases—molecule vibration increases, sliding past with greater ease

Pure substances are split into

Elements or Compounds

Mixtures are split into

Heterogeneous or Homogeneous

Pure substances are bonded—

Chemically

Mixtures are bonded—

Physically, non-chemically

In a group, atoms…

Increase going down vertically

In a period, atoms…

Decrease going horizontally

Reactivity in Alkalis…

Increases going down the group vertically

Reactivity in Halogens…

Decreases going down the group vertically

Noble Gases are…

Unreactive

Nucleus charge

Impacts atom size by increasing or decreasing

Fahrenheit

32 Freezing, 212 Boiling

Celsius

0 Freezing, 100 Boiling

Thermal Energy

Energy caused by temperature

Tem

Absolute Zero

Lowest temperature, molecules have the lowest energy they can (almost zero kinetic motion)

Kelvin

Starts at absolute zero, measures molecules relative to zero energy