Chemistry – Bonding and Reaction Types (finish deck and still read notes to understand periodic table trends) Flashcards
Atoms: structure, molecular mass
Structure: Atoms consist of a nucleus (containing protons and neutrons) surrounded by electrons in shells.
Molecular Mass: The sum of the atomic masses of all atoms in a molecule.
Identify how many protons, neutrons and electrons an atom has based on its atomic number and relative atomic mass.
Atomic Number (Z): Number of protons; equals the number of electrons in a neutral atom.
Relative Atomic Mass (A): Mass number = protons + neutrons.
Neutrons: Neutrons = A - Z
Atomic number
The number of protons in an atom’s nucleus, unique to each element.
Mass Number
The total number of protons and neutrons in an atom’s nucleus.
relative atomic mass of an atom
The weighted average mass of an element’s isotopes, compared to carbon-12.
Common properties of elements (alkali metals, alkaline earth metals, halogen and noble gas) (study further)
Alkali metals (Group 1): Highly reactive, soft, low melting points, form +1 ions.
Alkaline earth metals (Group 2): Less reactive, harder, higher melting points, form +2 ions.
Halogens (Group 17): Reactive non-metals, form -1 ions, exist as diatomic molecules.
Noble gases (Group 18): Inert, with full outer electron shells, unreactive.
Metals, non-metals and metalloids
Metals: Shiny, conductive, malleable, high melting and boiling points lose electrons to form cations.
Non-metals: Poor conductors, brittle, low melting and boiling points, gain electrons or share them in reactions.
Metalloids: Properties between metals and non-metals, semiconductors.
Electron configuration using the Bohr model
Structure of atoms in terms of electron shells
Energy of electrons to shells
Movement of electrons
Bohr Model: Electrons orbit the nucleus in fixed paths (energy levels).
Electron Shells: Shell 1 can hold 2, shell 2 can hold 8, shell 3 can hold 18, etc. (check these levels to see if right with old test)
Know the difference between ions, molecules and compounds
Ions: Charged atoms (cations = positive, anions = negative).
Molecules: Two or more atoms bonded together (can be the same or different).
Compounds: Pure substances made from two or more different elements.
Covalent Bond
A covalent bond is a chemical bond that involves the sharing of electrons to form electron pairs between atoms. Covalent bonding generally happens between nonmetals
Features/properties of ionic compounds, metals, covalent molecules
Ionic Compounds: High melting points, soluble in water, conduct electricity in solution.
Metals: Conductive, malleable, ductile.
Covalent Molecules: Lower melting points, can be gases or liquids.
Bonding: Putting together ionic compounds and covalent molecules (Covalent vs Ionic bonding)
Ionic Bonding: Transfer of electrons from one atom to another. Ionic bonds occur between metals, losing electrons, and nonmetals, gaining electrons.
Covalent Bonding: Sharing of electrons between non-metals
Identify a covalent bonded molecule by the presence of two non-metals bonded together via the sharing of electrons
Covalent Molecule: Formed by two non-metals sharing electrons.
Identify if a molecule contains single, double or triple bonds
Single Bond: One pair of shared electrons.
Double Bond: Two pairs of shared electrons.
Triple Bond: Three pairs of shared electrons.
Draw Lewis Dot Diagrams (electron dot diagrams)
Show valence electrons as dots around the element symbol.
Valency of an element (electrons it needs to gain, lose or share)
Valency: The number of electrons an element needs to gain, lose, or share to achieve stability.
Formula of simple covalent and ionic compounds (from valency of their constituent element)
Covalent Compounds: Combine based on shared electrons.
Ionic Compounds: Combine based on charges (balance the total charge).
Know the difference between reactants and products and understand the concept of ‘Conservation of mass’
Reactants: Substances that undergo a chemical change.
Products: Substances formed from the reaction.
Conservation of Mass: Mass of reactants equals mass of products.
Identify the signs of a chemical change
Color change, gas production, precipitate formation, temperature change.
Writing worded equations and balanced chemical equations
Worded Equations: Describe reactants and products in words.
Balanced Equations: Show equal numbers of each type of atom on both sides, with states.
Balancing chemical equations and writing states
Adjust coefficients to ensure the same number of atoms on each side.
Predict if a precipitation reaction will occur using solubility rules and identify the precipitate formed
Check solubility rules: If one of the products is insoluble in water, it forms a precipitate.
Identify the precipitate: The insoluble compound that forms a solid in the reaction.
Example: AgNO₃ + NaCl → AgCl (precipitate) + NaNO₃ (soluble).
Write worded and balanced chemical equations involving single and double displacement reactions, decomposition, combination, combustion, and neutralisation reactions.
Single Displacement: A + BC → AC + B
Double Displacement: AB + CD → AD + CB
Decomposition: AB → A + B
Combination: A + B → AB
Combustion: Hydrocarbon + O₂ → CO₂ + H₂O
Neutralization: Acid + Base → Salt + Water
Use the acid anion and base cation to determine the salt produced in a neutralisation reaction
Acid anion: Negative ion from the acid (e.g., Cl⁻ from HCl).
Base cation: Positive ion from the base (e.g., Na⁺ from NaOH).
To find the salt, combine the acid anion and base cation:
Example: HCl + NaOH → NaCl (salt) + H₂O.
Identify exothermic and endothermic reactions based on temperature change
Exothermic: Release heat (temp increase).
Endothermic: Absorb heat (temp decrease).
