Predict a simple reaction from the outer electrons
Grade 10 Science Worksheet - Challenge Me
Circle the best answer, or write your answer on the line.
Ari reacts 8 aluminum atoms (group 13) with oxygen gas (group 16). Electrons lost must equal electrons gained. How many O₂ molecules are used?
Bo reacts 12 magnesium atoms (group 2) with nitrogen gas (group 15). Electrons lost must equal electrons gained. How many N₂ molecules are used?
Esme reacts 12 lithium atoms (group 1) with oxygen gas (group 16). Electrons lost must equal electrons gained. How many O₂ molecules are used?
X is a main-group metal that forms X₂O₃ with oxygen. Which group is X in, Jun?
- Group 2, since each X atom loses 2 electrons
- Group 13, since each X atom loses 3 electrons
- Group 15, since each X atom gains 3 electrons
A compound has the formula M₃X₂. Which pair of ion charges fits, Kira?
- M³⁺ and X²⁻, since the subscripts swap places
- M²⁺ and X²⁻, since both ions carry the same size of charge
- M²⁺ and X³⁻, since 3 × (+2) cancels 2 × (−3)
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Magnesium reacting with nitrogen (example data)
measurement value magnesium used (g) 1.215 product formed (g) 1.683 magnesium molar mass (g/mol) 24.3 nitrogen molar mass (g/mol) 14.0 Using the table, which formula does the product have, Luz?
- MgN: one magnesium atom pairs with one nitrogen atom
- Mg₂N₃: the mole ratio of Mg to N is 2 to 3
- Mg₃N₂: 0.0500 mol of Mg to 0.0334 mol of N is 3 to 2
A student says nitrogen has 5 outer electrons, so it forms N⁵⁺. Which reply fits, Milo?
- Not supported: nitrogen reaches a full shell by gaining 3 electrons, forming N³⁻
- Supported: nitrogen is a nonmetal, and nonmetals lose their outer electrons
- Supported: an atom's charge matches its number of outer electrons, as with sodium
Element A ionization energies (real data, rounded)
step energy (kJ/mol) first 496 second 4,562 third 6,910 Using the table, how many outer electrons does element A have, Ren?
- 1: the energy jumps from 496 to 4,562 after the first electron
- 2: the energy rises by about 4,000, which counts two electrons
- 3: three energies are listed, so three electrons can be removed
Element B ionization energies (real data, rounded)
step energy (kJ/mol) first 738 second 1,451 third 7,733 Element B is a metal. Using the table, which formula does it form with chlorine, Tala?
- BCl, since the first electron comes off most easily
- BCl₂, since the big jump comes after the second electron
- BCl₃, since three energies are listed
Elements B and D ionization energies (real data, rounded)
step element B (kJ/mol) element D (kJ/mol) first 738 578 second 1,451 1,817 third 7,733 2,745 fourth not listed 11,577 Which element, B or D, is more likely to form a 3+ ion, Zee?
- B: its third energy, 7,733, is the largest in the table and so the most telling
- Both: each table lists a third energy, so each can lose three electrons
- D: energies rise gently through the third electron, then jump at the fourth