Atomic Structure
What are the three main subatomic particles in an atom?
Protons
Neutrons
Electrons
What type of reaction is: Na + Cl₂ → NaCl?
Synthesis reaction
Name the compound: NaCl
Sodium chloride
How many electrons are in the outer shell of oxygen?
6 valence electrons
What do all elements in a group (column) have in common?
Same number of valence electrons
What is the charge and location of a neutron?
Neutral charge, located in the nucleus
Balance the equation: H₂ + O₂ → H₂O
2H₂ + O₂ → 2H₂O
Write the formula for magnesium oxide
MgO
Draw a Bohr diagram for fluorine (F).
2 electrons in the first shell, 7 in the second shell
What trend increases as you move across a period from left to right?
Electronegativity and atomic number
What does the atomic number represent?
The number of protons in an atom
What is a combustion reaction? Provide an example.
A reaction with oxygen that produces CO₂ and H₂O; example: CH₄ + 2O₂ → CO₂ + 2H₂O
Is CO₂ an ionic or covalent compound? Name it.
Covalent; carbon dioxide
Draw a Lewis dot diagram for aluminum (Al).
Al with three dots around it (representing 3 valence electrons)
Which element is more reactive: sodium or lithium? Explain.
Sodium; it is further down Group 1, so it loses its outer electron more easily
How do you calculate the number of neutrons in an atom?
Subtract the atomic number from the mass number
In the reaction: AgNO₃ + NaCl → AgCl + NaNO₃, what type of reaction is this?
Double displacement reaction
Name this compound: Fe₂O₃ (include Roman numerals)
Iron(III) oxide
Explain the difference between a Bohr and a Lewis diagram.
Bohr shows all electrons in shells; Lewis shows only valence electrons
What is electronegativity? Which group has the highest electronegativity?
Tendency to attract electrons; Group 17 (halogens)
An ion has 17 protons and 18 electrons. What is its charge and identity?
Charge is -1; it is a chloride ion (Cl⁻)
What is the difference between a physical and chemical change? Give one example of each.
Physical: no new substance (e.g., melting ice); Chemical: new substance formed (e.g., rusting iron)
Write the name and formula for a compound made of calcium and nitrate.
Calcium nitrate; Ca(NO₃)₂
How many valence electrons does sulfur have, and how is this shown in a Lewis structure?
6 valence electrons, shown as 6 dots around the S
Why are noble gases unreactive?
They have full outer electron shells