Science 10 Chemistry and the Periodic Table

Comprehensive vocabulary flashcards covering matter classification, chemical and physical properties, historical organization of the periodic table, element families, atomic structure, and ions.

Matter

Anything that has mass and volume.

Mass

The amount of matter in a substance, typically measured in grams.

Volume

The amount of space a substance takes up, typically measured in liters.

Pure Substance

Matter that is made up of only one type of matter, such as water, gold, or oxygen.

Element

A pure substance that cannot be broken down into simpler substances (e.g., gold, oxygen).

Compound

A pure substance that is made up of two or more elements chemically combined together in a specific way.

Homogeneous Mixture

A mixture (solution) that is mixed uniformly so that its individual components cannot be seen (e.g., air, steel).

Heterogeneous Mixture

A mixture that contains distinct components that can be visibly seen (e.g., beach sand, salad dressing).

Physical Properties

Characteristics of matter that can be observed or measured without changing the chemical identity of the substance.

Chemical Properties

Characteristics that describe the ability of matter to react with another substance to form new substances (e.g., combustibility, lack of reactivity).

Precipitate

A solid that forms as a result of mixing two liquids during a chemical reaction.

Dmitri Mendeleev

The Russian teacher and chemist who, in the 1860s, organized elements by increasing atomic mass and grouped them into families with similar properties, leaving gaps for undiscovered elements.

Henry Moseley

The scientist who determined an element's atomic number, leading to the modern periodic table ordered by increasing atomic number.

Periods

The horizontal rows on the periodic table; atoms within the same row contain the same number of electron energy shells.

Families

The vertical columns on the periodic table containing elements that share similar chemical and physical properties and possess the same number of valence electrons.

Representative Elements

The elements located in Groups 1, 2, and 13 through 18 of the periodic table.

Transition Elements

The elements located in Groups 3 through 12 of the periodic table.

Metals

Elements found to the left of the zigzag line that are typically hard solids, lustrous, malleable, ductile, and good conductors of heat and electricity.

Non-Metals

Elements found to the right of the zigzag line that are typically dull, brittle, poor conductors of heat and electricity, and mostly gases at room temperature.

Alkali Metals

Group 1 elements (excluding hydrogen) that are shiny, soft, and highly reactive with water and oxygen.

Alkaline Earth Metals

Group 2 elements that are shiny and soft, and highly reactive (though less soft and less reactive than alkali metals).

Hydrogen

The lightest element, positioned on the left side of the periodic table; it is a colourless, odourless, tasteless, highly flammable gas that makes up over $90\%$ of all atoms in the universe.

Halogens

Group 17 elements that are poisonous, highly reactive, mostly found combined with water on Earth, and are gases at room temperature (except bromine, which is a liquid).

Noble Gases

Group 18 elements that are odourless, colourless gases possessing a complete outer valence shell, making them the least reactive elements of all.

Semi-Metals

Elements located along the staircase line (also known as metalloids) that exhibit physical and chemical properties of both metals and non-metals.

Silicon

A semi-metal that is shiny, brittle, and a poor conductor of heat and electricity; it is the second most abundant element in Earth's crust and is widely used in electronics.

Atom

The smallest unit of an element that retains the properties of that element, composed of a dense nucleus containing protons and neutrons surrounded by electrons in energy shells.

Proton

A positively charged subatomic particle located in the nucleus with a relative mass of $1836$ and the symbol $p^+$.

Neutron

An uncharged (neutral) subatomic particle located in the nucleus with a relative mass of $1837$ and the symbol $n^0$.

Electron

A negatively charged subatomic particle located in energy shells surrounding the nucleus with a relative mass of $1$ and the symbol $e^-$.

Atomic Number

The value indicating the number of protons in the nucleus of an atom, which also equals the number of electrons in an electrically neutral atom.

Atomic Mass

The total mass of an atom; subtracting the atomic number from the rounded atomic mass gives the total number of neutrons in the nucleus.

Valence Shell

The outermost electron energy shell of an atom.

Valence Electrons

The electrons located in the outermost energy shell of an atom that determine its chemical reactivity and bonding properties.

Ion

An electrically charged atom that has become stable by gaining electrons (non-metals) or losing electrons (metals) to achieve a full valence shell.