There are new ideas and questions that people are trying out and solving. Based off of that, the theories and ideas that we have now will change and evolve with the theories that have been tested and the questions that have been answered.
Answer: it reacts with the alkali metals (M) to form a salt MX, where X is the halogen.
Explanation: Group 7A elements are halogen and they react with alkali metals like Sodium or potassium to form a salt like NaCl
Easy (:
C₃H₈ (g) + O₂ (g) ---> CO₂ (g) + H₂O
1 C₃H₈ (g) + 5 O₂ (g) ---> 3 CO₂ (g) + 4 H₂O
With this there is the same amount of elements on each side (You take the larger number in front and multiply it by whats after it. So you have 3 C, 8 H, and 10 O on one side, and then the next mirrors is with 3 C, 8 H, and 10 O.
Rust is the chemical product that results when iron reacts with oxygen.