Elements compounds and mixtures

What is an element in chemistry?

An element is a pure substance that cannot be broken down into simpler substances, consisting of atoms with the same number of protons.

What is a compound?

A compound is a substance formed when two or more elements chemically bond together in fixed proportions.

What is a mixture?

A mixture is a combination of two or more substances that are not chemically combined and can vary in composition.

How are elements organized in the periodic table?

Elements are organized based on their atomic number, electron configurations, and recurring chemical properties.

What is atomic number?

The atomic number is the number of protons in the nucleus of an atom, which defines the element.

What are properties of metals?

Metals are typically shiny, malleable, ductile, and good conductors of heat and electricity.

What are properties of nonmetals?

Nonmetals are generally dull, brittle, and poor conductors of heat and electricity.

What are metalloids?

Metalloids have properties that are intermediate between metals and nonmetals, and they are often semiconductors.

What is a chemical bond?

A chemical bond is the force that holds atoms together in a compound.

What is the law of definite proportions?

The law of definite proportions states that a chemical compound contains the same proportion of elements by mass, regardless of its source.

What is a homogeneous mixture?

A homogeneous mixture has a uniform composition throughout, such as saltwater.

What is a heterogeneous mixture?

A heterogeneous mixture has a non-uniform composition, such as a salad or soil.

What is an example of a compound?

Water (H2O) is an example of a compound formed from hydrogen and oxygen.

What is the periodic table used for?

The periodic table is used to systematically organize elements and predict their chemical behavior based on their properties.

What is an ion?

An ion is an atom or molecule that has gained or lost one or more electrons, resulting in a net charge.

What are cations?

Cations are positively charged ions formed when an atom loses one or more electrons.

What are anions?

Anions are negatively charged ions formed when an atom gains one or more electrons.

What does 'reactivity' refer to in chemistry?

Reactivity refers to how readily a substance undergoes a chemical reaction.

What is a chemical reaction?

A chemical reaction is a process in which substances (reactants) transform into new substances (products).

What is the role of catalysts?

Catalysts speed up chemical reactions without being consumed in the process.

What is meant by 'solubility'?

Solubility is the ability of a substance to dissolve in a solvent, forming a solution.

What is an alloy?

An alloy is a mixture of two or more metals to enhance their properties.

What is the difference between a physical change and a chemical change?

A physical change alters the form of a substance without changing its chemical identity; a chemical change results in the formation of one or more new substances.

What is a solution?

A solution is a homogeneous mixture where one substance (the solute) is dissolved in another (the solvent).

What are the components of a chemical equation?

The components of a chemical equation include reactants, products, and coefficients that represent the quantity of substances involved.

What is pH a measure of?

pH is a measure of the acidity or basicity of a solution, indicating the concentration of hydrogen ions.

What is electrolysis?

Electrolysis is a chemical process that uses electricity to drive a non-spontaneous reaction, often used to separate elements from compounds.