Science Summative Test Flashcards
Describe a positive ion
Positive ions, or cations, are formed when an atom loses one or more electrons.
Describe a negative ion
Negative ions, or anions, are created when an atom gains one or more electrons.
Describe the formation of ionic bonds between ions of metallic and non-metallic elements, including the use of dot-and-cross diagrams
Metal Elements: Metals tend to have few electrons in their outer shell (valence electrons) and can lose these electrons easily to achieve a stable electron.
Non-Metal Elements: Non-metals have more electrons in their outer shell and tend to gain electrons to fill their valence shell.
Dot-and-cross diagrams visually represent the valence electrons of atoms and how they are transferred during ionic bond formation.
Describe and explain in terms of structure and bonding the properties of ionic compounds: (a) high melting points and boiling points (b) good electrical conductivity when aqueous or molten and poor when solid
High Melting and Boiling Points: Due to strong ionic bonds and high lattice energy.
Electrical Conductivity: Conducts well in molten or aqueous states due to mobile ions, while solid ionic compounds do not conduct electricity because ions are rigidly held in place.
State that a covalent bond is formed when a pair of electrons is shared between two atoms leading to noble gas electronic configurations
A covalent bond is formed when a pair of electrons is shared between two atoms. This sharing allows each atom to achieve a stable electron configuration, often resembling that of the nearest noble gas. By sharing electrons, the atoms effectively fill their outer shells, which enhances their stability.
Pt #1 Describe the formation of covalent bonds in simple molecules, including H2, Cl2, H2O, CH4, NH3 and HCl. Use dot-and-cross diagrams to show the electronic configurations in these and similar molecules
1) Two hydrogen atoms each have one electron in their outer shell.
They share their single electrons to form a covalent bond.
Pt #2 Describe the formation of covalent bonds in simple molecules, including H2, Cl2, H2O, CH4, NH3 and HCl. Use dot-and-cross diagrams to show the electronic configurations in these and similar molecules
2) Two chlorine atoms each have seven electrons in their outer shell.
They share one electron from each atom, forming a single covalent bond.
Pt #3 Describe the formation of covalent bonds in simple molecules, including H2, Cl2, H2O, CH4, NH3 and HCl. Use dot-and-cross diagrams to show the electronic configurations in these and similar molecules
3) One oxygen atom has six electrons in its outer shell, while each hydrogen atom has one.
The oxygen atom shares one electron with each hydrogen atom, forming two covalent bonds.
Pt #4 Describe the formation of covalent bonds in simple molecules, including H2, Cl2, H2O, CH4, NH3 and HCl. Use dot-and-cross diagrams to show the electronic configurations in these and similar molecules
4) A carbon atom has four electrons in its outer shell, while each hydrogen atom has one.
The carbon atom shares one electron with each of the four hydrogen atoms, forming four covalent bonds.
Pt #5 Describe the formation of covalent bonds in simple molecules, including H2, Cl2, H2O, CH4, NH3 and HCl. Use dot-and-cross diagrams to show the electronic configurations in these and similar molecules
5) One nitrogen atom has five electrons in its outer shell, while each hydrogen has one.
The nitrogen atom shares one electron with each of the three hydrogen atoms, forming three covalent bonds.
Pt #6 Describe the formation of covalent bonds in simple molecules, including H2, Cl2, H2O, CH4, NH3 and HCl. Use dot-and-cross diagrams to show the electronic configurations in these and similar molecules
6) The chlorine atom has seven electrons in its outer shell, and hydrogen has one.
They share one pair of electrons to form a single covalent bond.
Pt #1 Describe the formation of covalent bonds in simple molecules, including CH3OH, C2H4, O2, CO2 and N2. Use dot-and-cross diagrams to show the electronic configurations in these and similar molecules
In methanol, a carbon atom shares one electron with three hydrogen atoms and one with an oxygen atom.
Oxygen shares one electron with carbon and has two lone pairs remaining.
Pt #2 Describe the formation of covalent bonds in simple molecules, including CH3OH, C2H4, O2, CO2 and N2. Use dot-and-cross diagrams to show the electronic configurations in these and similar molecules
In ethylene, each carbon atom has four valence electrons. They share two pairs of electrons between them (a double bond) and each shares one electron with two hydrogen atoms.
Pt #3 Describe the formation of covalent bonds in simple molecules, including CH3OH, C2H4, O2, CO2 and N2. Use dot-and-cross diagrams to show the electronic configurations in these and similar molecules
Each oxygen atom has six electrons in its outer shell. They share two pairs of electrons to form a double bond, achieving a full outer shell of eight electrons.
Pt #4 Describe the formation of covalent bonds in simple molecules, including CH3OH, C2H4, O2, CO2 and N2. Use dot-and-cross diagrams to show the electronic configurations in these and similar molecules
The carbon atom shares two pairs of electrons with each of the two oxygen atoms, resulting in two double bonds, effectively achieving stable configurations for all involved atoms.
Pt #5 Describe the formation of covalent bonds in simple molecules, including CH3OH, C2H4, O2, CO2 and N2. Use dot-and-cross diagrams to show the electronic configurations in these and similar molecules
Each nitrogen atom has five electrons in its outer shell. They share three pairs of electrons to form a triple bond, giving each nitrogen atom a full outer shell.
Pt #1 Describe and explain in terms of structure and bonding in terms of structure and bonding the properties of simple molecular compounds: (a) low melting points and boiling points (b) poor electrical conductivity
Low Melting and Boiling Points: This is due to weak intermolecular forces that require less energy to overcome compared to the strong ionic or metallic bonds in other types of compounds.
Pt #2 Describe and explain in terms of structure and bonding in terms of structure and bonding the properties of simple molecular compounds: (a) low melting points and boiling points (b) poor electrical conductivity
Poor Electrical Conductivity: Simple molecular compounds lack free ions or delocalized electrons, preventing them from conducting electricity effectively.
Define the molecular formula of a compound as the number and type of different atoms in one molecule
Water (H₂O): The molecular formula indicates that there are 2 hydrogen atoms and 1 oxygen atom in each molecule.
Glucose (C₆H₁₂O₆): This molecular formula shows that each glucose molecule contains 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms.
Construct word equations and symbol equations to show how reactants form products, including state symbols: Methane, water hydrogen and oxygen, calcium carbonate, reaction between hydrochloric acid and sodium hydroxide.
Combustion of Methane
Word Equation: Methane + Oxygen → Carbon Dioxide + Water
Symbol Equation: CH₄(g) + 2 O₂(g) → CO₂(g) + 2 H₂O(g)
Formation of Water from Hydrogen and Oxygen
Word Equation: Hydrogen + Oxygen → Water
Symbol Equation: 2 H₂(g) + O₂(g) → 2 H₂O(l)
Decomposition of Calcium Carbonate
Word Equation: Calcium Carbonate → Calcium Oxide + Carbon Dioxide
Symbol Equation: CaCO₃(s) → CaO(s) + CO₂(g)
