1.1- INSIDE THE ATOM Flashcards
How small is an atom?
less than a millionth of a millimeter in diameter
What two things does every atom contain that was shown by Rutherford’s alpha-scattering investigations?
positively charged nucleus composed of protons and neutrons
electrons that surround the nucleus
What word is used for a proton or a neutron in the nucleus?
nucleon
How are electrons held in the atom?
electrostatic force of attraction between them and the nucleus (opposite charge)
What did Rutherford’s investigation show?
nucleus contains most of the mass of the atom
its diameter is of the order 0.00001 times the diameter of a typical atom
What is the mass of an electron in comparison to the nucleons?
electrons have a much smaller mass than the proton or the neutron
What is the mass of protons and neutrons like in comparison to each other?
protons and neutrons have an almost equal mass
What is the charge of protons, neutrons and electrons like?
electrons have an equal and opposite charge to protons
neutrons are uncharged
What happens when an uncharged atom becomes an ion?
it gains or loses electrons
What is known about every atom of a given element?
it has the same number of protons as any other atom of the same element
What is the same term as proton number?
atomic number
What is an isotope?
atoms of the same element with different numbers of neurons
What is the nucleon number/mass number?
total number of protons and neutrons in an atom
Why is the name of the total number of protons and neutrons in an atom called the mass number?
it is almost numerically equal to the mass of the atom is relative units (where the mass of a proton or neuron is approximately 1)
What is a nucleon?
neutron or a proton in the nucleus
