Atomic Structure & The Periodic Table Flashcards
(26 cards)
Element
Definition: A substance made of only one type of atom.
Sentence: Oxygen is an element because it only contains oxygen atoms.
Atom
Definition: The smallest unit of matter that retains the properties of an element.
Sentence: Every element is made up of atoms.
Proton
Definition: A positively charged particle found in the nucleus of an atom.
Sentence: A carbon atom has 6 protons in its nucleus.
Neutron
Definition: A particle with no charge found in the nucleus of an atom.
Sentence: Neutrons help keep the nucleus stable.
Electron
Definition: A negatively charged particle that orbits the nucleus in energy levels.
Sentence: Electrons are involved in bonding between atoms.
Atomic Number
Definition: The number of protons in an atom’s nucleus.
Sentence: Hydrogen has an atomic number of 1, meaning it has one proton.
Mass Number
Definition: The total number of protons and neutrons in an atom’s nucleus.
Sentence: Carbon has a mass number of 12 (6 protons + 6 neutrons).
Electron Configuration
Definition: The arrangement of electrons in energy levels around the nucleus.
Sentence: The electron configuration of oxygen is 2,6.
Dalton’s Model
Definition: Dalton proposed that atoms are tiny, indivisible spheres.
Sentence: Dalton’s model was the first scientific model of the atom.
Thomson’s Model
Definition: Thomson described atoms as spheres with embedded electrons (plum pudding model).
Sentence: Thomson’s model introduced the idea of negatively charged particles.
Rutherford’s Model
Definition: Rutherford discovered the nucleus and said electrons orbit it, with most of the atom being empty space.
Sentence: Rutherford’s gold foil experiment led to a new model of the atom.
Bohr’s Model
Definition: Bohr suggested electrons orbit the nucleus in fixed energy levels.
Sentence: Bohr’s model helped explain atomic emission spectra.
Scientific Models
Definition: Simplified representations that explain observations and make predictions.
Sentence: Changes in atomic models occurred as new evidence was discovered.
Periodic Table
Definition: A table organizing elements by increasing atomic number and similar properties.
Sentence: The Periodic Table helps predict an element’s properties.
Group
Definition: A vertical column in the Periodic Table; elements in a group have similar properties.
Sentence: Group 1 elements are highly reactive metals.
Period
Definition: A horizontal row in the Periodic Table; properties change gradually across a period.
Sentence: Period 2 elements have two electron shells.
Metal
Definition: Elements that are shiny, conduct electricity, and tend to lose electrons.
Sentence: Iron is a common metal used in construction.
Non-metal
Definition: Elements that are poor conductors and tend to gain electrons.
Sentence: Oxygen is a non-metal that supports life.
Semi-metal
Definition: Elements with properties of both metals and non-metals.
Sentence: Silicon is a semi-metal used in electronics.
Mendeleev
Definition: Russian scientist who arranged elements by atomic mass and predicted missing ones.
Sentence: Mendeleev’s Periodic Table left gaps for undiscovered elements.
Ion
Definition: A charged atom formed when electrons are lost or gained.
Sentence: Sodium forms a positive ion by losing one electron.
Ionic Compound
Definition: A compound formed between a metal and non-metal by the transfer of electrons.
Sentence: Sodium chloride is an ionic compound.
Covalent Bond
Definition: A chemical bond where atoms share electrons.
Sentence: In water, each hydrogen forms a covalent bond with oxygen.
Covalent Compound
Definition: A compound made of non-metals sharing electrons.
Sentence: Carbon dioxide is a covalent compound.
