Explain how different observations and experiments led to changes in the atomic model. explain how line spectra are used to identify elements and what they indicate about atoms. represent electron arrangements using electron configuration, orbital notation, shorthand notation, and lewis dot notation. apply the rules and limitations of each quantum number to identify possible and impossible quantum number sets.

> Explain how different observations and experiments led to changes in the atomic model.

The atomic model has progressed over time. As scientists have learned more about the atoms, the atomic model has changed.

Democritus: first proposed that matter cannot be divided into smaller pieces

Dalton: created the 1st atomic theory. He viewed atoms as tiny solid balls

JJ Thomson: discovered electrons, he showed that atoms are made of even smaller things

Rutherford: discovered protons and nucleus, he showed that atoms have positive particles in the center and that atoms are made up mostly of empty space

Bohr: improved Rutherford’s model by proposing that electrons move around the nucleus in layers or shells

Chadwick: discovered neutrons = particles with no charge

The modern model of the atom is made up of works collaborated since 1920 which has electrons moving around the nucleus in a cloud.

> Explain how line spectra are used to identify elements and what they indicate about atoms.

Actually each element has its own unique spectra, hence this property can be used to identify the element. The line spectra give us an indication about the energy levels of the electrons, and each wavelength produces different colors.

> Represent electron arrangements using electron configuration, orbital notation, shorthand notation, and Lewis dot notation.

To answer your question, I will illustrate an example. The s orbital can accommodate 2 electrons, p orbital can accommodate 6, d orbital can accommodate 10, f orbital can accommodate 14. To take as example, Mg contains 12 electrons using the Aufbau principle, the electron configuration is: 1s2 2s2 2p6 3s2 the numbers after the letter represent the amount of electrons, the letters (s, p) represent the sublevel of the electron, while the number before the letter represent the principal quantum number, or "level".

Apply the rules and limitations of each quantum number to identify possible and impossible quantum number sets.

>There are four quantum numbers.

1. Principal quantum number (n) can take values of any positive whole numbers

2. Angular momentum quantum number (l) is from 0 to n – 1

3. Magnetic quantum number (ml) is from –l to +l

4. Spin quantum number (ms) only takes two values, positive spin and negative spin: +1/2, -1/2

From these rules you can identify possible and impossible set of quantum numbers.

Ans. : frostbite is when exposure to cold temperatures causes freezing to the skin or other tissues. it most commonly affects the hands, feet, and face. the longer areas are exposed to cold, typically the worse the frostbite. the water temperature used for rewarming a frostbitten part should be : (102 -105) f degrees.

Aseasonal prevailing wind in the region of south and southeast asia, blowing from the southwest between may and september and bringing rain (the wet monsoon ), or from the northeast between october and april (the dry monsoon ).