science
Chemical Property
Definition: A chemical property is a characteristic of a substance that describes its ability to undergo chemical reactions or change into a new substance.
Physical Property
Definition: A physical property is a characteristic of a substance that can be observed or measured without changing its chemical composition.
Example: Density is a physical property of a substance, and it is determined by dividing its mass by its volume.
Mixture:
Definition: A mixture is a combination of two or more substances in which each substance retains its individual properties.
Pure Substance:
Definition: A pure substance is a substance that consists of only one type of atom or molecule with distinct chemical properties.
Example: Oxygen gas (O2) is a pure substance because it is composed of only oxygen molecules.
Element
Definition: An element is a pure substance composed of only one type of atom.
Example: Hydrogen (H) is an element because it consists of only hydrogen atoms.
Compound
Definition: A compound is a substance made up of two or more different elements chemically combined in fixed proportions.
Example: Water (H2O) is a compound consisting of two hydrogen atoms and one oxygen atom.
Atom:
Definition: An atom is the smallest unit of an element that retains the chemical properties of that element.
Example: A carbon atom (C) is the basic unit of carbon, with a nucleus composed of protons and neutrons and electrons orbiting the nucleus.
Proton
Definition: A proton is a positively charged subatomic particle found in the nucleus of an atom.
Example: Hydrogen has one proton in its nucleus.
Neutron
Definition: A neutron is a neutrally charged subatomic particle found in the nucleus of an atom.
Example: Carbon has six neutrons in its nucleus
Electron
Definition: An electron is a negatively charged subatomic particle found in the electron cloud outside the nucleus of an atom.
Example: Oxygen has eight electrons in its electron cloud.
Isotope:
Definition: Isotopes are atoms of the same element with the same number of protons but a different number of neutrons.
Example: Carbon-12 and Carbon-14 are isotopes of carbon.
Atomic Number:
Definition: The atomic number is the number of protons in the nucleus of an atom.
Example: The atomic number of oxygen (O) is 8, indicating it has 8 protons.
Atomic Mass
Definition: Atomic mass is the average mass of an element's isotopes, taking into account their abundance.
Example: The atomic mass of carbon is approximately 12.01 atomic mass units (amu).
Cation
Definition: A cation is a positively charged ion formed when an atom loses electrons.
Example: A sodium ion (Na+) is a cation formed when a sodium atom loses one electron.