Question

I'll award a medal for the help!

1. Describe the current model of the atom.

2. How is the periodic table of elements arranged?

3. Compare and contrast physical changes and chemical changes.

4. Design an experiment that could be used to demonstrate a chemical or physical change. Explain what makes it a chemical or physical change and explain what happens to mass and energy

5. Design an activity that you could use to teach someone else about the laws of conservation of mass and energy.

Answer 1

1. The current model of the atom consists of a nucleus and an electron cloud. The nucleus contains the protons and neutrons. The electron cloud houses the electron. However, the exact position of the electrons cannot be determined but the probability of finding them in a particular state can be calculated.
2. The periodic table of elements is arranged based on the number of protons (increasing from left to right). Vertically, the elements are grouped based on the number of valence electrons (elements with the same number of valence electrons belong to the same group).
3. Chemical changes involve changes that lead to the formation of a new substance. Physical changes, on the other hand, are simply changes that do not affect the chemical composition of the original substance.
4. Physical change experiment: Melting of ice. Both ice and water have the same chemical formula, H2O.
Chemical change experiment: Burning of wood. The burnt wood has different chemical composition compared to the original material.
5. When cooking in an isolated system, the masses (and therefore the energy) of both the initial ingredients and final product should be the same.