Definitions Flashcards
What is an atom?
An atom is the smallest particle of an element.
What is an element?
An element is composed of the same type of atom.
What is a compound?
A compound is two or more elements chemically bonded together.
What is a molecule?
A molecule is two or more atoms covalently bonded together.
What is an ion?
An ion is a charged particle.
What is a cation?
A cation is a positively charged ion.
What is an anion?
An anion is a negatively charged ion.
What are nucleons?
Nucleons are the sub-atomic particles that exist in the nucleus of atoms (protons & neutrons).
What holds protons and neutrons together in the nucleus?
The strong nuclear force holds together protons & neutrons in the nucleus.
What forces exist between positive and negative particles?
Electrostatic forces of attraction exist between any positive and negative particles.
What are isotopes?
Isotopes are atoms of the same element with different numbers of neutrons.
What is relative atomic mass?
Relative atomic mass (A) is the average mass of an atom of an element compared to one twelfth of the mass of one atom of carbon-12.
What is relative isotopic mass?
Relative isotopic mass is the mass of an atom of an isotope compared to one twelfth of the mass of one atom of carbon-12.
What is atomic number?
Atomic number is the number of protons in the nucleus of an atom of that element.
What does A represent in atomic structure?
A = mass number (no. of protons + neutrons in the nucleus).
What is a species in chemistry?
A species in chemistry is a substance composed of chemically identical entities.
What is relative molecular mass?
Relative molecular mass (M) of a compound is the sum of the relative atomic masses of all the atoms in a molecule compared to one twelfth of the mass of one atom of carbon-12.
What is relative formula mass?
Relative formula mass (M) of an ionic compound is the sum of the relative atomic masses of all the atoms in the formula compared to one twelfth of the mass of one atom of carbon-12.
What is a main shell or quantum shell?
A main shell or quantum shell is made up of sub-shells containing orbitals, where electrons are found.
What is an orbital?
An orbital is a region of space in an atom containing up to two electrons with opposite spins.
What is a sub-shell?
A sub-shell is one or more orbitals in the same shell which have the same energy levels.
What characterizes an s-block element?
An s-block element has its highest energy electron in an s orbital.
What characterizes a p-block element?
A p-block element has its highest energy electron in a p orbital.
What characterizes a d-block element?
A d-block element has its highest energy electron in a d orbital.
What are transition metals?
Transition metals are elements which form at least one stable ion with partially filled d orbitals.
What is first ionisation energy?
First ionisation energy is the energy required to remove one mole of electrons from one mole of atoms in the gaseous state.
[ M(g) → M*(g) + e ]
What is second ionisation energy?
Second ionisation energy is the energy required to remove one mole of electrons from one mole of 1+ ions in the gaseous state.
[ M(g) → M2(g) + e ]
What is successive ionisation energy?
Successive ionisation energy is the energy required to remove the electrons one after the other.
What is periodicity?
Periodicity is a regularly repeating pattern of atomic, physical and chemical properties with increasing atomic number.
