Atoms, Molecules, and Bonding

Module 2 Written Assignment- Atoms, Molecules, and Bonding

The Atom Model

1. Light

1. How fast does light travel? 186,000 miles / second
2. Define Wavelength:  The distance between any two adjacent comparable points on a wave, such as distance from one trough to the next.
3. How many nanometers are seen as:

1. Red light: 700 nm
2. Yellow light:  590 nm
3. Green light:  500 nm
4. Blue light:  450 nm
5. Violet light:  400 nm

1. Visible light has a wavelength between    380   nm and   750  nm
2. The diagram below shows the electromagnetic spectrum.[pic 1]
3. What is the energy of yellow light that has a wavelength of 580nm?

E=(6.626 X 10-34 J X s)(3.00 X 108 m / s) = 1.9878 X 10-25  = 3.4272414 X 10-19 J

       (580 nm)(1.0 X 10-9 m / nm)                     5.8 X 10-7

3.43 X 10-19 J

1. What are some of the serious side effects of violet light to humans?

Ultraviolet light can cause sunburns, x-ray exposure can cause cancer and gamma rays may result in death.

1. What are some common uses of red light?

Red light is used in microwaves, as well as, radio and television waves.

1. Physics

1. Define:  

1. Classical Physics:  Physics as described by Newton and as it was understood until the end of the nineteenth century before the discovery that energy can be quantized. The laws of classical physics work well when applied to everyday objects because at that level the fact that energy can be quantisized can be ignored but the laws fail when applied to objects that are the size of atoms and electrons
2. Quantum physics:  Physics that take into account the fact that energy is quantisized and therefore can be used to describe the behavior of atoms and subatomic particles

1. Bohr’s Theory of Atomic Structure

1. Define Bohr’s Theory: A theory of atomic structure in which the hydrogen atom is assumed to consist of a proton nucleus with a single electron moving in distinct circular orbits around it. Each orbit corresponding to a specific quantized energy state.

1. Bohr assigned each of his allowed electron orbits, called shells, principle quantum number (n).  Each shell can hold a fixed maximum number of electrons.  The larger the shell, the more electrons it can hold.  Fill in the chart with the electron capacities.

1. The number of electrons in the valence shell of an atom is equal to the roman-numeral group number for the representative (A group) elements.
2. Define the Ground state of an atom: The state in which all of its electrons are arranged so as to have the lowest possible total energy. The arrangement in which each electron occupies the lowest energy sub shell available
3. Define the Excited state of an atom:  A state in which one or more electrons have absorbed energy and jumped from their ground state position to a higher energy shell or sub shell leaving behind an electron vacancy
4. Define Relaxation:  The process by which an excited electron falls to a lower energy level

1. Subshells

1. Define subshells:  A subdivision of an electron shell, designated s, p, d and f with s being of the lowest energy

1. How many electrons can be in each subshell, fill in the chart:[pic 2]

1. Electron Configuration

1. In which period and group is the element that has the ground-state electron configuration 1s22s22p63s23p64s23d3? Vanadium lies in group 5 period 4

1. Variations in element properties

1. Metals prefer to   lose  valence electrons
2. Nonmetals prefer to   gain  valence electrons.
3. Atomic radius   increase   as you go down in a group
4. Atomic radius    decreases  as you go from left to right in a period.

1. Ionization energy

1. Define Ionization energy as it relates to the periodic table: The amount of energy to remove an electron from an atom or ion. Each electron in any atom has specific ionization energy. Ionization energy increases (becomes more difficult to remove) as you go down a group and decreases as you go from left to right.

1. Octet Rule

1. Define Octet rule:

1. Explain how the octet rules pertains to NaCl (table salt):

All atoms strive to have a full outer shell. Sodium has only one electron in its outer shell, so it can either gain seven or lose one electron. Losing one takes less energy as with chlorine that has seven in its outer shell it is more energy efficient for chlorine to take up the one electron from sodium so they each achieve a full outer shell.