Quarter 1 Reflection

By 1809 about 47 elements had been discovered and named. Scientists began to see patterns in their atom structures.

John Newlands organized the 56 then known elements into eleven separate groups based upon their atom structure.

Dimitri Mendellev used John Newlands' grouping and organized the elements into what is now known as the periodic table. He used the atomic mass as the primary characteristic to decide where each element belonged in his table.  The elements were arranged in rows and columns. He even left spaces for elements to be discovered because of the pattern he saw once he started organizing those elements known at that that time.

 

Elements are arranged in the Periodic Table in order of increasing atomic number. The Periodic Table allows chemists to make accurate predictions of physical properties and chemical behaviour for any element based on its position.

 

Throughout the quarter we learned about several trends of the periodic table, such as electronegativity, ionization energy, ionic radii, electron affinity, and atomic radii. To expand our understanding on these trends, our project was to come up with a way of explaining the trend on the periodic table. Each person had an assigned trend, and would have to develop a presentation for his/her classmates. This way, everyone would get a better understanding of each trend. My trend was electron affinity.

 

Electron Affinity is the likelihood of a neutral atom of gaining an electron. It is defined as the change in energy (in kJ/mole) when it gains an electron. It increases negatively as you go across a period and up a group. It increases as you go across a period because the elements in group 17 need to gain an electron in order to gain the stability of a noble gas, while the elements in group 1 need to lose an electron to gain the stability of a noble gas. It increases as you go up a group because the radius of the element gets smaller as you go up, so elements with smaller radius have less shielding so they are able to attract electrons more strongly.

To present my trend, I created a periodic table of men, varying in age and in acne level. I came up with a ‘scale’ of acne, from 1-10, As you go down a group, the age increases from 15 years old to 59 years old. And as you go across a period, from left to right, the level of acne increases, meaning the younger you are (being a teenager) the higher level of acne you have, and as you get older, you have less acne.