Periodic Table & Reactivity
Which group contains the most reactive metals?
Group 1 (alkali metals)
What is the oxidation state of sodium (Na) in NaCl?
What is +1
Name the five types of chemical reactions.
What is Synthesis, Decomposition, Single Replacement, Double Replacement, Combustion
What do you change to balance a chemical equation?
What are coefficients
What type of reaction releases energy: exothermic or endothermic?
What is exothermic
How does reactivity change as you move down Group 17?
What is reactivity increases as you move up, decreases as you move down
Write the electron configuration for Oxygen.
What is 1s2 2s2 2p4
What type of reaction is this? 2H2O2 → 2H2O + O2
What is Decomposition
Balance this: HBr + KOH → KBr + H20
What is its already balanced
Define activation energy.
What is the energy required to start a reaction
Why do elements in the same group have similar properties?
What is elements in the same group have the same number of valence electrons, resulting in similar chemical properties.
How do oxidation states help predict chemical formulas?
What is oxidation states indicate charges that help balance chemical formulas by ensuring that the total charge is neutral.
List two signs that a chemical reaction has occurred.
What is color change, temperature change, gas production, precipitate formation
Why can’t you change subscripts when balancing?
What is changing subscripts alters the compound’s identity and chemical properties.
In an exothermic reaction, are products higher or lower in energy than reactants?
What is the reactivity trend across a period (left to right)?
What is reactivity decreases from left to right across a period for metals; increases for nonmetals.
What does an electron configuration ending in 3s2 3p5 tell you about the element?
What is 3s2 3p5 indicates the element is a halogen with 7 valence electrons, likely to gain 1 electron.
Describe what happens in a combustion reaction
What is combustion reactions involve a hydrocarbon burning in the presence of oxygen to produce heat/light, CO₂, and H₂O
Balance and identify reaction type: Fe+O2 → Fe2O3
What is
Balanced: 4Fe+3O2→2Fe2O3
Reaction type: Synthesis (Combination)
What is bond energy?
What is energy required to break bonds in reactants or released when bonds form in products
Explain how electron configuration relates to an element’s reactivity.
What is electron configuration shows valence electrons, which determine how easily an element gains or loses electrons, affecting reactivity.
Explain how to determine the oxidation state of an element from its group number.
What is group number (for main group elements) often equals the number of valence electrons; oxidation states are based on gaining/losing electrons to complete octet.
How does a single replacement reaction differ from a double replacement?
What is single replacement involves one element replacing another; double replacement involves exchange of ions between two compounds.
Explain how balancing equations relates to the law of conservation of mass.
What is balancing ensures mass is conserved; atoms are neither created nor destroyed in reactions.
Explain the difference between exothermic and endothermic reactions using energy diagrams.
What is exothermic releases energy (products lower energy), endothermic absorbs energy (products higher energy); energy diagrams show these changes with activation energy peaks.