HS-PS1-2: Trends of the Periodic Table

HS-PS1-2:  Construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.

This video covers important trends of the periodic table.  Topics include; reactivity, ionization energy, successive ionization energy, atomic radius, ionic radius, electron affinity, and electronegativity.

Comments

Post a Comment

Popular posts from this blog

Radioactive Decay of Cesium-137

Image
This video shows a sample of cesium-137 being tested for emission of radiation.  Nuclei of cesium-137 isotopes are unstable and will undergo a process of radioactive decay to form more stable isotopes.  Cesium-137 is formed during fission reactions of uranium-235 in nuclear power plants and nuclear weapons. The equation that describes the radioactive decay of cesium is shown below.  The conversion of a neutron (from the cesium nucleus) to a proton causes the atomic number to increase from 55 to 56.  This leads to the formation of barium-137.  It's important to notice that the mass number stays the same in examples of beta decay. 137 Cs → 137 Ba + 0 e 55 56 -1
Read more

How do we know the universe is getting bigger?

Image
To understand the evidence that the universe is getting larger, we need to understand the Doppler effect.  This is the reason why a siren from a police car or fire truck has a higher pitch as it is approaching and a lower pitch when it is traveling away from us. The two images below are really useful in trying to better understand the Doppler effect. The first image has a stationary red dot which is giving off waves, which is shown by the concentric blue circles.  The wavelengths of the waves being given off are represented by the distance between the concentric blue circles.  The waves would appear the same to four observers each located at the corners of the square area.  The second image shows waves being produced by a moving object.  In this case, the waves would appear to be different to observers on the right or left side of the square area.  Observers on the left side would observe waves that are stretched out because the object giving off the waves is moving away from
Read more