Atoms

• An atom consists of protons, neutrons and electrons.
• Isotopes are atoms with different numbers of neutrons but same number of protons
• The mass number is the sum of protons and neutrons
• The number of protons is the atomic number
• Neutrons have no charge and are also located in the nucleus of an atom.
• Protons are positively charged particles found in the nucleus of an atom.
• The nucleus is the central part of an atom, containing protons and neutrons.
• Protons have a positive charge, neutrons have no charge, and electrons have a negative charge.
• Atoms consist of a nucleus, which contains protons and neutrons, and electrons that orbit the nucleus in energy levels.
• Atomic structure can be represented by a periodic table or electron configuration diagram
• Atomic number = number of protons
• Electron configurations show how many electrons there are in each energy level (shell)
• Mass number = number of protons + number of neutrons
• Electrons orbit around the nucleus at different energy levels called shells or electron clouds.
• Electron configuration shows how many electrons are in each energy level
• Electrons are negatively charged particles that orbit around the nucleus of an atom.
• Atomic radius increases as we move down a group on the periodic table due to increased shielding by inner shells.
• Electrons orbit around the nucleus at different distances from it.
• Electron shells are regions around the nucleus where electrons can be found.
• A chemical symbol represents an individual type of atom.
• Elements with similar properties appear together on the periodic table due to their similar number of outermost electrons
• Ions are atoms that have gained or lost electrons, resulting in a net positive or negative charge
• Isotopes - atoms with same atomic number but different mass numbers due to varying amounts of neutrons
• Ions are charged particles formed when an atom gains or loses electrons
• The atomic mass is the average mass of all naturally occurring isotopes of an element
• Atomic radius decreases as we go down group 1 because there are more shells to fit into so it takes up more space
• Relative atomic mass (Mr) is an average value that takes into account all naturally occurring isotopes
• Atomic radius increases as we move down group one on the periodic table due to increased shielding by inner shells.
• Protons have a positive charge (+1) and are found in the nucleus of an atom.
• Atomic radius increases as we move down group one on the periodic table due to increased shielding by inner shells.
• Ionisation energy increases going across period 3 because the nucleus has further away from the electron cloud which means that the attraction between the nucleus and the outermost electron is stronger
• Shells with more than one sub-level are referred to as sub-shells.
• Les constituants de la matière sont représentés par les entités chimiques et l'électroneutralité.
• Les entités chimiques peuvent être principalement des atomes, des ions ou des molécules.
• Les composés ioniques permettent d'illustrer le phénomène de l'électroneutralité de la matière, fondamental à cette échelle.
• Une espèce chimique est un ensemble de nombreuses entités identiques qu'on appelle entités chimiques qui peuvent être principalement des atomes, des ions ou des molécules.
• Les atomes, les ions et les molécules constituent les principales entités chimiques à l'échelle microscopique.
• L'atome est le constituant fondamental de la matière et est électriquement neutre.
• Un échantillon de fer ne contient que des atomes de fer, dont le symbole est Fe.
• Une molécule est un assemblage d'atomes liés entre eux, elle est électriquement neutre.