C1.2 Atomic Structure Flashcards
Atom
The smallest particle of an element that can exist, consisting of a nucleus and electrons.
Nucleus
The central part of an atom containing protons and neutrons.
Proton
A positively charged particle found in the nucleus of an atom.
Neutron
A neutral particle found in the nucleus of an atom.
Electron
A negatively charged particle that orbits the nucleus in shells.
Atomic Number
The number of protons in the nucleus of an atom, which defines the element.
Mass Number
The total number of protons and neutrons in the nucleus of an atom.
Isotope
Atoms of the same element that have the same number of protons but different numbers of neutrons.
Electron Shell
The region around the nucleus where electrons are found. Electrons occupy energy levels or shells.
What is the relative mass of a proton?
1
What is the relative mass of an electron?
0 or 0.0005
What is the relative mass of a neutron?
1
Explain the electron shell rules.
The first shell can have 2, the second and third have 8 each and the fourth can only have 2.
Ion
An atom with the same number of neutrons and protons and but with a different number of electrons
Isotope
An atom with the same number of protons but with a different number of electrons.
Dalton’s Model
Proposed in the early 1800s, Dalton suggested that atoms are indivisible particles, and each element consists of identical atoms. He also proposed that atoms combine in fixed ratios to form compounds.
Thomson’s Model
In 1897, J.J. Thomson discovered the electron and proposed the “plum pudding model,” suggesting that atoms are a positively charged sphere with negatively charged electrons embedded within, like raisins in a pudding.
Rutherford’s Model
In 1911, Ernest Rutherford conducted the gold foil experiment, leading to the discovery of the nucleus. His model proposed that an atom consists of a small, dense, positively charged nucleus surrounded by electrons in a mostly empty space.
Bohr’s Model
Niels Bohr developed his model in 1913, introducing the idea of quantized electron orbits around the nucleus. Electrons occupy specific energy levels, and energy is absorbed or emitted when electrons move between these levels.
Gold Foil Experiment
Conducted in 1909 under the supervision of Ernest Rutherford, this experiment involved firing alpha particles at a thin sheet of gold foil. Most particles passed through, but a small fraction were deflected at large angles. This unexpected result led to the conclusion that atoms have a small, dense, positively charged nucleus at their center, surrounded by mostly empty space where electrons are located. The experiment provided crucial evidence for the nuclear model of the atom and fundamentally changed the understanding of atomic structure.
Chadwick’s Model
In 1932, James Chadwick discovered the neutron, proposing that it, along with protons, resides in the nucleus. This discovery explained the mass of the atom and led to a better understanding of nuclear stability.
Give your answer in the form (n:1).
What is the ratio between the atomic and nucleic radii.
10000:1
