atomic structure and the periodic table

• What is an atom?

  An atom is the basic unit of matter that consists of a nucleus containing protons and neutrons, surrounded by electrons.
• What does the periodic table show?

  The periodic table shows the elements and their properties.
• What is a compound?

  A compound is a substance composed of two or more elements chemically bonded together.
• What is a mixture?

  A combination of two or more substances that are not chemically bonded.
• What are the processes by which a mixture is separated?

  Filtration, distillation(simple and fractional), chromatography, evaporation.
• How did the old plum pudding model describe the structure of the atom?

  The old plum pudding model described the atom as a positively charged sphere with negatively charged electrons embedded in it.
• Which experiment to the discovery of the nucleus?

  Rutherford's gold foil experiment.
• How did the nuclear model of the atom differ from the plum pudding model?

  Nucleus
• What detail about electrons did Bohr add to the nuclear model?

  Energy levels or electron shells.
• Who discovered the neutron in the nucleus?

  James Chadwick
• What are the relative masses of a proton, neutron, and electron?

  1,1, almost 0
• What is the overall electrical charge of an atom?

  Neutral
• What is the radius of the typical atom?

  0.1 nanometres
• What are the relative electrical charges of a proton, neutron, and electron?

  Proton: +1 Neutron: 0 Electron: -1
• what is the mass number of the atom?

  The mass number of an atom is the total number of protons and neutrons in its nucleus.
• What is an isotope?

  An isotope is a variant of an element that has the same number of protons but a different number of neutrons in its nucleus.
• What does the atomic number of the element tell you?

  The number of protons in the nucleus of an atom.
• Why are some elements' atomic masses, not whole numbers?

  Isotopes
• Electrons occupy different energy levels around an atom. What are these energy levels also known as?

  Orbitals
• How many electrons occupy each energy level?

  It depends on the energy level. 2, 8, 8, 18
• How are the elements of the periodic table ordered?

  By increasing atomic number.
• How are elements in the periodic table grouped?

  Elements in the periodic table are grouped based on their similar chemical properties and electron configurations.
• How many electrons are in the outer shell of group 2 elements?

  2
• What is an ion?

  An electrically charged particle, formed when an atom or molecule gains or loses an electron.
• Do metals form positive or negative ions?

  positive
• Are metals found on the left or right of the periodic table?

  Left
• In which group of the periodic table are all elements unreactive?

  Noble gases
• Why are the noble gases unreactive?

  Full electron shells.
• What are elements in group 1 known as?

  Alkali metals
• Why are alkali metals so reactive?

  Atoms get larger, the outer electron gets further from the nucleus as you go down the group. Attraction between the nucleus and outer electron is weaker so the electron is easier to lose.
• How does the reactivity of elements in group 1 change as you go down?

  Increases
• Which group contains the halogens?

  Group 7
• How does reactivity change as you go down group 7?

  Decreases.
• How does melting point of the halogens change as you go down the group?

  Increases