C2 Bonding, structure and properties of matter

• What are ions in chemistry?


  Ions are charged particles that can be single atoms or groups of atoms.
• How do ions form?

  Ions are formed when atoms lose or gain electrons to achieve a full outer shell like noble gases.
• What happens when metals form ions?

  Metals lose electrons from their outer shell to form positive ions.
• What is the relationship between the number of electrons lost or gained and the charge of the ion?

  The number of electrons lost or gained is equal to the charge on the ion.
• Which groups of elements are most likely to form ions?

  Groups 1, 2, 6, and 7 are the most likely to form ions.
• What type of ions do Group 1 and 2 elements form?

  Group 1 and 2 elements are metals that lose electrons to form positive ions (cations).
• What type of ions do Group 6 and 7 elements form?

  Group 6 and 7 elements are non-metals that gain electrons to form negative ions (anions).
• What do elements in the same group have in common regarding ion formation?

  Elements in the same group have the same number of outer electrons and lose the same number to achieve a full outer shell.
• What charge do Group 2 elements form when they become ions?

  Group 2 elements form 2+ ions.
• What charge do Group 6 elements form when they become ions?

  Group 6 elements form 2- ions.
• What charge do Group 7 elements form when they become ions?

  Group 7 elements form 1- ions.
• How does a sodium atom (Na) form a sodium ion (Na+)?


  A sodium atom loses 1 electron to form a sodium ion with the same electronic structure as neon: Na → Na+ + e.
• How does a magnesium atom (Mg) form a magnesium ion (Mg2+)?

  A magnesium atom loses 2 electrons to form a magnesium ion with the same electronic structure as neon: Mg → Mg2+ + 2e.
• How does a chlorine atom (Cl) form a chloride ion (Cl-)?

  A chlorine atom gains 1 electron to form a chloride ion with the same electronic structure as argon: Cl + e → Cl-.
• How does an oxygen atom (O) form an oxide ion (O2-)?

  An oxygen atom gains 2 electrons to form an oxide ion with the same electronic structure as neon: O + 2e → O2-.
• What is ionic bonding?

  • Ionic bonding involves the transfer of electrons between a metal and a non-metal.
  • Metals lose electrons to form positive ions (cations).
  • Non-metals gain electrons to form negative ions (anions).
  • The oppositely charged ions are attracted to each other by electrostatic forces, forming an ionic bond.
• What do dot and cross diagrams represent in ionic compounds?

  Dot and cross diagrams show the arrangement of electrons in an atom or ion, indicating which electrons came from which atom.
• How does sodium chloride (NaCl) form from sodium (Na) and chlorine (Cl)?

  The sodium atom gives up its outer electron, becoming an Na+ ion, while the chlorine atom picks up the electron, becoming a Cl- ion.
• How does magnesium oxide (MgO) form from magnesium (Mg) and oxygen (O)?

  The magnesium atom gives up its outer electrons, becoming an Mg2+ ion, while the oxygen atom picks up the electrons, becoming an O2- ion.
• How does magnesium chloride (MgCl2) form from magnesium (Mg) and chlorine (Cl)?

  The magnesium atom gives up its outer electrons, becoming an Mg2+ ion, while two chlorine atoms each pick up one electron, becoming two Cl- ions.
• How does sodium oxide (Na2O) form from sodium (Na) and oxygen (O)?

  Two sodium atoms each give up their single outer electron, becoming two Na+ ions, while the oxygen atom picks up the two electrons, becoming an O2- ion.
• What are the properties of ionic compounds?

  • High melting points and boiling points due to strong ionic bonds.
  • Do not conduct electricity when solid, but conduct when melted or dissolved in water.
  • Some ionic compounds dissolve in water, allowing ions to move freely and carry electric charge.
• How do you determine the empirical formula of an ionic compound from a diagram?

  Count the number of atoms of each element in the diagram and balance the charges of the ions to ensure the overall charge is zero.
• What is the empirical formula of a compound containing potassium (K) and oxide (O) ions?

  The empirical formula is K2O, as two potassium ions (1+ charge) balance one oxide ion (2- charge).
• What is covalent bonding?

  • Covalent bonding involves the sharing of pairs of electrons between atoms.
  • The positively charged nuclei of the bonded atoms are attracted to the shared pair of electrons by electrostatic forces.
  • Atoms share electrons in their outer shells to achieve a full outer shell, similar to noble gases.
• How are covalent bonds represented in diagrams?

  Covalent bonds can be represented using dot and cross diagrams, displayed formulas, or 3D models.
• What is the molecular formula of ethane (C2H6) based on its diagram?

  The molecular formula of ethane is C2H6, as it contains two carbon atoms and six hydrogen atoms.
• What are simple molecular substances?

  • Simple molecular substances are made up of molecules containing atoms joined together by covalent bonds.
  • Examples include hydrogen (H2), methane (CH4), and water (H2O).
• What type of bond do hydrogen atoms form with each other?

  Hydrogen atoms form single covalent bonds with each other.
• How does carbon form covalent bonds in methane (CH4)?

  Carbon forms four covalent bonds with hydrogen atoms to fill its outer shell.
• How do chlorine atoms bond with each other?

  Two chlorine atoms share one pair of electrons to form a single covalent bond.
• How do nitrogen atoms bond with each other?

  Two nitrogen atoms share three pairs of electrons to form a triple bond.
• How does water (H2O) form covalent bonds?

  In water, the oxygen atom shares a pair of electrons with two hydrogen atoms to form two single covalent bonds.
• How does hydrogen chloride (HCl) form covalent bonds?

  In hydrogen chloride, the hydrogen atom shares one electron with the chlorine atom to form a single covalent bond.
• What do atoms need to achieve a complete outer shell?

  Atoms need to share or gain electrons.
• What type of bond is formed when two oxygen atoms share electrons?

  A double covalent bond is formed.
• How many outer electrons does carbon have?

  Carbon has four outer electrons.
• How does carbon fill its outer shell?

  Carbon forms four covalent bonds with hydrogen atoms.
• What do two chlorine atoms do to complete their outer shells?

  They share one pair of electrons to form a single covalent bond.
• How many electrons do nitrogen atoms need to fill their outer shells?

  Nitrogen atoms need three more electrons.