JLSS Science - Chemistry

Matter

Anything that has mass and takes up space.

Elements and compounds

What are the two types of pure substances?

Element

A substance made of only one kind of atom; cannot be broken down.

Compound

A substance made of two or more elements chemically combined in fixed ratios.

No

Can a pure substance be separated by physical means?

Mixture

A combination of two or more substances that are not chemically bonded and can be separated physically.

Homogenous

A type of mixture that is uniform throughout (e.g., saltwater);

Heterogenous

A type of mixture with visibly different parts (e.g., salad).

Physical property

A characteristic observed without changing the substance (e.g., color, melting point).

Chemical property

Describes how a substance reacts to form a new substance (e.g., flammability).

Filtration

What method separates solid from liquid?

Evaporation or distillation

What method separates dissolved solids from liquids?

Distillation

What method separates liquids with different boiling points?

Chromatography

What method separates components based on solubility and movement through paper?

Decanting

Heavier solid or liquid from top layer

Proton + electron - neutron 0

What are the three main subatomic particles and their charges?

Nucleus

Where are protons and neutrons found?

Atomic number Z

The number of protons in an atom. It defines the element.

Proton + neutron

What is mass number?

Isotope

Atoms of the same element with different numbers of neutrons.

Ionic bond

Bond between nonmetal + metal

transferred

In ionic bonding, electrons are?

covalent

Bond type between nonmetal + nonmetal

shared

In covalent bonding, elements are?

polar covalent

Unequal sharing of electrons

Nonpolar covalent bond

Equal sharing of electrons

same element

How to quickly tell if a covalent bond if nonpolar?

Atom

smallest unit of an element that retains the properties of that element.

A - Z

How to calculate neutrons?

Anion -

Ions that have more electrons than protons.

Cation +

Ions that have fewer electrons that protons

Choose the highest energy level

How to subtract electrons in election configuration?