C1-Atomic structure and periodic table

• What is the radius of an atom?

  0.1 nm
• What is the radius of a nucleus?

  -latex>1 \times 10^{-14}text{ m}</latex>
• What does it mean that atoms have no overall charge?

  It means the number of protons equals the number of electrons.
• What is the relative mass and charge of a proton?

  Relative mass is 1 and charge is +1.
• What is the relative mass and charge of a neutron?

  Relative mass is 1 and charge is 0.
• What is the relative mass and charge of an electron?

  Relative mass is very small and charge is -1.
• What does the mass number represent in nuclear symbols?

  It represents the total number of protons and neutrons in an atom.
• What is the atomic number in nuclear symbols?

  It is the number of protons in an atom.
• What are elements and isotopes?

  • Elements: Substances made up of atoms with the same atomic number.
  • Isotopes: Atoms with the same number of protons but different numbers of neutrons.
• What is relative atomic mass (A_r)?

  It is the average mass number for an element based on isotope abundance.
• What is a compound and a molecule?

  • Compound: A substance formed from two or more elements chemically bonded together in fixed proportions
  • Molecule: A particle containing two or more non-metal atoms bonded covalently.
• What happens in a chemical reaction?

  At least one new substance is made, and energy change can be measured.
• What is an example of a chemical formula?

  CO₂
• What do chemical formulas and equations represent?

  • Chemical formula: Shows the proportion of atoms of each element in a compound.
  • Chemical equation: Shows the overall change in a reaction.
• What is the purpose of balancing a chemical equation?

  To ensure the same number of each atom on both sides of the equation.
• What are mixtures and how can they be separated?

  • Mixtures: Substances made up of different elements or compounds that aren’t chemically bonded.
  • Separation: Can be done by physical methods without chemical reactions.
• What is an example of a mixture?

  Air
• What is filtration and evaporation used for?

  • Filtration: Separates insoluble solids from liquids.
  • Evaporation: Separates soluble salts from solutions.
• What is crystallisation used for?

  To separate soluble salts from solutions and form large crystals.
• What are the two types of distillation?

  • Simple distillation: Separates liquids with different boiling points.
  • Fractional distillation: Separates liquids with similar boiling points.
• What is the significance of the Bohr model of the atom?

  It describes electrons orbiting the nucleus in fixed shells.
• What did James Chadwick discover?

  He provided evidence that neutrons are neutral particles found in the nucleus.
• What is the electronic structure of an atom?

  • Electrons occupy shells or energy levels.
  • Fill each shell before occupying a new one, starting with the lowest energy.
• How many electrons can fit in the first three shells of an atom?

  2, 8, and 8 respectively.
• How did Mendeleev organize his periodic table?

  • Grouped elements by properties.
  • Left gaps for undiscovered elements.
• What is the modern periodic table based on?

  It is ordered by increasing atomic number.
• What do the group and period numbers indicate in the periodic table?

  • Group number: Number of electrons in the outer shell.
  • Period number: Number of shells with electrons.
• What are the general properties of metals and non-metals?

  • Metals: Shiny, strong, high melting/boiling points, good conductors.
  • Non-metals: Dull, brittle, low melting/boiling points, poor conductors.
• How do metals and non-metals achieve full outer shells?

  Metals lose electrons, while non-metals gain or share electrons.
• What are the trends in Group 1 elements?

  • Reactivity increases down the group.
  • Melting and boiling points decrease.
  • Relative atomic mass increases.
• What are the properties of Group 1 metals?

  • More reactive than most metals.
  • Less dense and softer.
  • Lower melting points.
• What reactions do Group 1 elements undergo?

  They react with water, chlorine, and oxygen to form ionic compounds.
• What are Group 0 elements known for?

  • Non-metals with full outer shells.
  • Unreactive and colorless monatomic gases at room temperature.
• What are the trends in Group 7 elements?

  • Reactivity decreases down the group.
  • Melting and boiling points increase.
  • Relative molecular mass increases.
• How do halogens achieve a full outer shell?

  By sharing electrons or gaining an electron to form ionic compounds.
• What happens when more reactive halogens react with less reactive ones?

  More reactive halogens can displace less reactive ones.
• What is the appearance of fluorine?

  Yellow gas
• What is the appearance of chlorine?

  Pale green gas
• What is the appearance of bromine?

  Volatile red-brown liquid
• What is the appearance of iodine?

  Dark grey or purple solid