Energy, elements, atoms, and bonding

Question 1

Distinguish between kinetic and potential energy

Answer 1

Kinetic - energy that an object or particle has because of it’s motion
Potential - energy stored in an object, it can be related to it’s position or chemical energy.
Examples - Metabolism(kinetic)

Question 2

List the main chemical elements essential to life

Answer 2

Oxygen, Hydrogen, Carbon, Nitrogen

Question 3

Subatomic particles that make up an atom

Answer 3

-Nucleus = protons and neutrons

-Electrons

Question 4

Isotope and an example of one

Answer 4

All atoms of a given element have the same number of protons, but some atoms have more neutrons than other atoms of the same element and therefore have greater mass. These different atomic forms of the same element are called isotopes of the element.
E.g. 12C 13C 14C
Same atomic number, different number of neutrons means different atomic mass

Question 5

The orbitals of an atom

Answer 5

-Filled orbitals are more stable than unfilled

-Elements with incomplete valence shells can interact with other elements to form bonds

-Unpaired or valence electrons are able to interact with other unpaired electrons to complete the valence shell.

Question 6

Covalent, hydrogen, ionic, van der Waal’s bonds

Answer 6

Covalent bonds – sharing of electrons by 2 atoms
- Non-polar (equal sharing of
electrons) e.g. Hydrogen/H2/H-H
- Polar (Not equal sharing) e.g. OH in H2O
bonds

Hydrogen bonds – Molecules with polar bonds, together strong

Ionic bonds – type of linkage formed(crystal formed) from the electrostatic attraction between oppositely charged ions in a chemical compound. Very strong

Van der Waal’s forces –very weak, short range, happen between molecules that are very near

Question 7

Preferred number of electrons in the outer shell of an atom

Answer 7

1s – 2e

2s – 2e

2P- 6e