Atomic Structure and Periodic Table

A pure substance made up of only one type of atom, defined by the number of protons in its nucleus.

Horizontal rows in the Periodic Table, indicating the number of electron shells an atom has.

Vertical columns in the Periodic Table containing elements with similar properties and the same number of valence electrons.

Highly reactive metals that naturally exist as compounds with other elements. They are soft, shiny, and have low densities and melting points.

Also highly reactive, these metals are harder than alkali metals and are good conductors of heat and electricity.

Hard, shiny solids with high thermal and electrical conductivity. They are often found in alloys and are good conductors of heat and electricity.

Elements with three valence electrons, including metals and metalloids, some of which are semiconductors.

Elements with four valence electrons, including nonmetals, metalloids, and metals. They are essential for organic compounds.

The distance between the nucleus of an atom and its outermost electron shell.

The force of attraction between the nucleus and electrons in an atom. It increases as the number of protons increases, making the atom smaller.

The size of an ion, which is an atom that has gained or lost electrons.

The energy required to remove an electron from a gaseous atom, creating a positive ion.

Elements with five valence electrons. They include nonmetals and metalloids and commonly form nitrogen-based compounds.

Elements with six valence electrons. They include oxygen and sulfur and are essential for life, forming a variety of compounds.

Highly reactive nonmetals that react violently, especially with metals. They are poor conductors of heat and electricity, and have low melting and boiling points.

Colorless, odorless, and nonflammable gases under standard conditions. They are the most stable elements, with eight valence electrons, making them inert and unreactive.

A principle that states electrons fill the lowest energy orbitals first before moving to higher energy ones. Orbitals are filled in a specific order, starting with 1s.

The principle that dictates only two electrons can occupy an orbital, and they must have opposite spins. This accounts for the different energy states of electrons.

A rule that states each orbital must receive one electron before any orbital can receive a second electron. It helps explain the filling of orbitals with multiple electrons.

The number that indicates the energy level of an electron in an atom. It's a positive integer starting with 1 for the lowest energy level.

Indicates the shape of an electron orbital. It can be s, p, d, or f, representing different shapes and energy levels.

The ability of an atom to attract electrons towards itself when forming a chemical bond.

All matter is composed of tiny indivisible particles called 'atomos'.

All elements are made up of tiny particles called 'atoms'. All atoms of a particular element are identical. The atoms of one element are different from another element. Atoms of an element can combine with atoms of another element to form compounds. Atoms are indivisible, they can’t be created nor destroyed in chemical reactions.

Discovered electrons, negative particles within atoms. Proposed the atom is a 'plum pudding' with electrons embedded in a positively charged 'pudding'.

Positive charge is not like a pudding but it's concentrated in the nucleus. Concluded that atoms have a dense, positively charged nucleus with electrons surrounding it.

Electrons in an atom occupy certain orbits with quantized energies. Atoms have allowable energy states. Electrons revolve in stable orbitals around a nucleus. Atoms have certain allowable energy states

It's impossible to know exactly where an electron is at any moment. There is uncertainty in the position and motion of the electron.

It is a map of the probably location of the electrons. It helps us predict the orbitals' possible location, shape, and energy of the location

In a chemical reaction, mass is neither created nor destroyed. The total mass of reactants equals the total mass of products. Atoms are rearranged but not lost or gained.

A statement using symbols to represent a chemical reaction. It shows reactants, products, and the direction of the reaction.

A chemical equation that uses words to describe a reaction. Example: Aluminum and Chlorine react to form Aluminum Chloride.

A chemical equation that uses symbols to represent the reaction but doesn't balance the number of atoms on each side.

Using prefixes like mono-, di-, tri-, etc., to indicate the number of atoms in a covalent compound. Example: CO₂ = Carbon dioxide.

Naming covalent compounds by naming the first element with a prefix (if more than one atom) and the second element with the prefix and '-ide' ending. Example: CO₂ = Carbon dioxide.

A method of balancing ionic charges in a compound by crisscrossing the numerical values of the charges and using those as subscripts. Example: Na⁺ + Cl⁻ → NaCl.

Naming ionic compounds by naming the cation first (no prefix), then the anion with '-ide' ending. For transition metals, use Roman numerals for the charge. Example: NaCl = Sodium chloride, FeCl₂ = Iron (II) chloride.

A chemical reaction where two or more simple substances combine to form a more complex substance. Example: A + B → AB

A chemical reaction where a compound breaks down into two or more simpler compounds or elements. Example: AB → A + B

A chemical reaction where an element replaces another element in a compound. Example: A + BC → AC + B

A chemical reaction where two compounds exchange cations to produce two different compounds. Example: AB + CD → AD + BC

A chemical reaction that happens when a hydrocarbon reacts with oxygen, producing energy in the form of heat and light. Example: CxHy + O2 → CO2 + H2O (Complete Combustion) CxHy + O2 → C + CO + H2O (Incomplete Combustion)

The minimum amount of energy needed to start a chemical reaction. Higher activation energy means a slower reaction, and lower activation energy means a faster reaction.

The speed at which reactants are converted into products. A faster rate means the reaction happens quickly, while a slower rate means it takes longer.

Increasing the surface area of reactants will make the reaction happen faster because more particles are exposed and can interact.