"The structure of the atom is key to the majority of the techniques used in radiology, and a general understanding of atomic structure is worthwhile. An atom is the smallest constituent of a chemical element that still maintains the chemical properties of that element.The following is a simplified overview of the structure of the atom."
"The composition of an atom is - in classical physics - principally 'empty space'; the relative dimensions of the nucleus/atom are 10-15 m (1 femtometre) and 10-10 m (1 angstrom). Its mass is concentrated within the central nucleus which is composed of a specific number of nucleons. Nucleons are either protons or neutrons, and the total number of nucleons is assigned the symbol A (also known as the mass number). The total number of protons within the nucleus is called the atomic number and assigned the symbol Z (the A and Z symbols are always italicised in atomic physics). Protons and neutrons are each assigned a relative mass of one."
"The composition of an atom is - in classical physics - principally 'empty space'; the relative dimensions of the nucleus/atom are 10-15 m (1 femtometre) and 10-10 m (1 angstrom). Its mass is concentrated within the central nucleus which is composed of a specific number of nucleons. Nucleons are either protons or neutrons, and the total number of nucleons is assigned the symbol A (also known as the mass number). The total number of protons within the nucleus is called the atomic number and assigned the symbol Z (the A and Z symbols are always italicised in atomic physics). Protons and neutrons are each assigned a relative mass of one."
"The composition of an atom is - in classical physics - principally 'empty space'; the relative dimensions of the nucleus/atom are 10-15 m (1 femtometre) and 10-10 m (1 angstrom). Its mass is concentrated within the central nucleus which is composed of a specific number of nucleons. Nucleons are either protons or neutrons, and the total number of nucleons is assigned the symbol A (also known as the mass number). The total number of protons within the nucleus is called the atomic number and assigned the symbol Z (the A and Z symbols are always italicised in atomic physics). Protons and neutrons are each assigned a relative mass of one."
"The composition of an atom is - in classical physics - principally 'empty space'; the relative dimensions of the nucleus/atom are 10-15 m (1 femtometre) and 10-10 m (1 angstrom). Its mass is concentrated within the central nucleus which is composed of a specific number of nucleons. Nucleons are either protons or neutrons, and the total number of nucleons is assigned the symbol A (also known as the mass number). The total number of protons within the nucleus is called the atomic number and assigned the symbol Z (the A and Z symbols are always italicised in atomic physics). Protons and neutrons are each assigned a relative mass of one."
"In classical physics, the electrons orbit the nucleus in a similar way to planets orbiting the sun (Rutherford–Bohr model). They orbit in one of the 'shells' that surround the nucleus: these are named K, L, M, N etc. from the centre outwards. The number of electrons each shell can contain is 2n2 (where n = number of the shell)."
"In classical physics, the electrons orbit the nucleus in a similar way to planets orbiting the sun (Rutherford–Bohr model). They orbit in one of the 'shells' that surround the nucleus: these are named K, L, M, N etc. from the centre outwards. The number of electrons each shell can contain is 2n2 (where n = number of the shell)."
"The first “scientist” to consider, albeit theoretically, the intimate constitution of the matter was – in the fifth century BCE – the Greek philosopher Democritus. He hypothesised the existence of the atom (from the Greek word for 'indivisible', 'indestructible') as that portion of matter that cannot be further divided 5."
"The first “scientist” to consider, albeit theoretically, the intimate constitution of the matter was – in the fifth century BCE – the Greek philosopher Democritus. He hypothesised the existence of the atom (from the Greek word for 'indivisible', 'indestructible') as that portion of matter that cannot be further divided 5."
"The composition of an atom is - in classical physics - principally 'empty space'; the relative dimensions of the nucleus/atom are 10-15 m (1 femtometre) and 10-10 m (1 angstrom). Its mass is concentrated within the central nucleus which is composed of a specific number of nucleons. Nucleons are either protons or neutrons, and the total number of nucleons is assigned the symbol A (also known as the mass number). The total number of protons within the nucleus is called the atomic number and assigned the symbol Z (the A and Z symbols are always italicised in atomic physics). Protons and neutrons are each assigned a relative mass of one."
"The composition of an atom is - in classical physics - principally 'empty space'; the relative dimensions of the nucleus/atom are 10-15 m (1 femtometre) and 10-10 m (1 angstrom). Its mass is concentrated within the central nucleus which is composed of a specific number of nucleons. Nucleons are either protons or neutrons, and the total number of nucleons is assigned the symbol A (also known as the mass number). The total number of protons within the nucleus is called the atomic number and assigned the symbol Z (the A and Z symbols are always italicised in atomic physics). Protons and neutrons are each assigned a relative mass of one."
"The composition of an atom is - in classical physics - principally 'empty space'; the relative dimensions of the nucleus/atom are 10-15 m (1 femtometre) and 10-10 m (1 angstrom). Its mass is concentrated within the central nucleus which is composed of a specific number of nucleons. Nucleons are either protons or neutrons, and the total number of nucleons is assigned the symbol A (also known as the mass number). The total number of protons within the nucleus is called the atomic number and assigned the symbol Z (the A and Z symbols are always italicised in atomic physics). Protons and neutrons are each assigned a relative mass of one."
"The composition of an atom is - in classical physics - principally 'empty space'; the relative dimensions of the nucleus/atom are 10-15 m (1 femtometre) and 10-10 m (1 angstrom). Its mass is concentrated within the central nucleus which is composed of a specific number of nucleons. Nucleons are either protons or neutrons, and the total number of nucleons is assigned the symbol A (also known as the mass number). The total number of protons within the nucleus is called the atomic number and assigned the symbol Z (the A and Z symbols are always italicised in atomic physics). Protons and neutrons are each assigned a relative mass of one."
"The composition of an atom is - in classical physics - principally 'empty space'; the relative dimensions of the nucleus/atom are 10-15 m (1 femtometre) and 10-10 m (1 angstrom). Its mass is concentrated within the central nucleus which is composed of a specific number of nucleons. Nucleons are either protons or neutrons, and the total number of nucleons is assigned the symbol A (also known as the mass number). The total number of protons within the nucleus is called the atomic number and assigned the symbol Z (the A and Z symbols are always italicised in atomic physics). Protons and neutrons are each assigned a relative mass of one."
"A (mass number): total number of nucleons = protons + neutrons"
"Z (atomic number): number of protons"
"A (mass number): total number of nucleons = protons + neutrons"
"Z (atomic number): number of protons"
"K: 2 electrons"
"NB: It is now known, from quantum theory, that the electrons are not in 'shells' but occupy specific energy levels, i.e. are quantised, but for the purposes of Radiopaedia the simplistic shell model suffices."
"The first “scientist” to consider, albeit theoretically, the intimate constitution of the matter was – in the fifth century BCE – the Greek philosopher Democritus. He hypothesised the existence of the atom (from the Greek word for 'indivisible', 'indestructible') as that portion of matter that cannot be further divided 5."
Expected headings
"Nucleus"
"Orbiting electrons"
"The composition of an atom is - in classical physics - principally 'empty space'; the relative dimensions of the nucleus/atom are 10-15 m (1 femtometre) and 10-10 m (1 angstrom). Its mass is concentrated within the central nucleus which is composed of a specific number of nucleons. Nucleons are either protons or neutrons, and the total number of nucleons is assigned the symbol A (also known as the mass number). The total number of protons within the nucleus is called the atomic number and assigned the symbol Z (the A and Z symbols are always italicised in atomic physics). Protons and neutrons are each assigned a relative mass of one."
"Protons and neutrons are not elementary particles; they each consist of quarks (three) and gluons. Two up quarks and one down quark form the proton; two down quarks and one up quark form the neutron. Protons are positively charged; neutrons have no charge (specifically, the algebraic sum of the electric charges of their constituents is zero) 4."
"Protons and neutrons are not elementary particles; they each consist of quarks (three) and gluons. Two up quarks and one down quark form the proton; two down quarks and one up quark form the neutron. Protons are positively charged; neutrons have no charge (specifically, the algebraic sum of the electric charges of their constituents is zero) 4."
"Protons and neutrons are not elementary particles; they each consist of quarks (three) and gluons. Two up quarks and one down quark form the proton; two down quarks and one up quark form the neutron. Protons are positively charged; neutrons have no charge (specifically, the algebraic sum of the electric charges of their constituents is zero) 4."
"The composition of an atom is - in classical physics - principally 'empty space'; the relative dimensions of the nucleus/atom are 10-15 m (1 femtometre) and 10-10 m (1 angstrom). Its mass is concentrated within the central nucleus which is composed of a specific number of nucleons. Nucleons are either protons or neutrons, and the total number of nucleons is assigned the symbol A (also known as the mass number). The total number of protons within the nucleus is called the atomic number and assigned the symbol Z (the A and Z symbols are always italicised in atomic physics). Protons and neutrons are each assigned a relative mass of one."