Lab 7.2 Periodic Trends Activity

The heaviest elements in a period have the smallest radii because as you go across a period from left to right , the elements have more protons, forcing a much stronger pull on the electron shells toward the nucleus, making the radius smaller. The heaviest elements have smaller radii because they have more protons, which makes the pull stronger.

As you go down a group the electronegativity decreases, because as you go further down the list of elements in a grou, the element gains more metallic characteristics. The more mettalic an element is the more likely is it to lose electrons. When elements are larger in size they have a lower electronegativity because it has more shells and since more shells make it father from the nucleus, it lessens the attraction of the electrons.

As you go from left to right on the periodic table, the ionization energy increases. This is because metals are more likely to lose electrons than non-metals. As you move right on the periodic table, the elments start to gain non-metals characteristics , which makes it harder to lose electrons because they normally gain electrons.

The trends are reffered as periodic because trends are repeated periodically or at regular intervals.

Lab 7.3 Reactivity of Metals.

Lab Questions. 


Do Elements that are in the same Period or those that are in the same Group have more similiraties in their properties ? 

Elements that are in the same Group have more similiraties in their properties, because of their valence electrons and also during the lab i made some observation of the element that were in the same Group. K & Na are from Group 1 on the periodic table during the lab i observed 5 similarities between them.

• Float in water.
• Exothermic reaction.
• Reaction with water is fast.
• Produce gas.
• Reaction with air is fast.

thats how i concluded that elements that are in the same Group have more similarities than elements that are in the same Period.

Elements in the same group tend to have very similar properties because they have the same valence electron for example in Group 2 Be electron configuration is 2-2, Mg electron configuration is 2-8-2 they both have the same valence electron which is 2.  I grouped K & Na because they valence electron is 1 and during the experiment i made similar observation about both of them which means they must have similar properties.

When an aton of sodium atom interacts with an aton of a nonmetal it will.

• Loses electrons
• Be a positive ion 
• The charge will be +1
• It will become like the noble gas Neon
• More stable.

Enrichment:

When you mix NaCl and Cacl, it produces 99% of pure sodium metal, which is what chemists use as pure Sodium. Obviously you need to have the right amounts in order to do so.

Lab 7.1 Flame Tests and Emission Spectra

1. An element spectra is often called its fingerprint because every element has its own unique spectrum,when an electron return to ground state from the excited state, light is emitted at specific frequencies. Spectra lines are like an element's fingerprint. They are unique and can be used to identify the element.An atom in the excited state is unstable and will immediately emit the energy in the form of light as electrons return to the ground state. The excited state configuration of an atom has the same number of electrons as the ground state.
2. When an element is changing from ground state to an excited state, the electrons absorb energy and move to higher energy levels. Shortly after, the electrons return to a lower energy level and release energy. As this happens the Bright-line spectra is formed. This is based off of specific frequencies that the element's electrons had given off. 

Enrichment:
The origin of the element Helium involves Greek mythology. It is named after the God of the sun, Helios.
A red shift happens when increased wavelengths of light bounce off of objects, or shifted to the red side of the spectrum. A blue shift happens when decreased wavelengths of light bounce around and it becomes shifted towards the blue side of the spectrum. Because of the increasing wavelengths in red shifts, the distances of objects get much larger. Edwin Hubble proved that there are galaxies other than our own. He also discovered that the degree of the redshift observed in the light spectra from other galaxies increased in proportion to another galaxy's distance from earth. This helped establish the fact that the universe is expanding.