Trends in the periodic table and bonding HC CHEMISTRY HC CHEMISTRY (B) Periodicity Trends in the periodic table and bonding Overview This section studies how the elements are arranged in the Periodic Table, the structure and bonding of the first twenty elements, Helps you explain key periodic trends in physical properties and relate these to the bonding continuum.

HC HC THE ATOMIC WORLD 1pm = 0.000000000001m (B) Periodicity CHEMISTRY HC CHEMISTRY (B) Periodicity THE ATOMIC WORLD After completing this topic you should be able to : Be familiar with atomic structure and how atoms are structured ( N5 revision). Be able to describe electrostatic force of attraction (also known as Coulomb’s force) holding electrons in orbitals. Understand the scale of measurement required when exploring the depth of atomic structure. Know that the radius of a typical atom is one trillionth of a meter and the units of distance at this scale is the picometer 1 x10-12 meters . 1pm = 0.000000000001m

N5 Revision

Uncertainty principle The methods we use to visualize the position of electrons are not suitable to find the exact location of an electron. This is because, in-order to visualise the electron, we need to project some energy on the electron, which in turn makes the electron go to a higher energy state.  For Ex: If you want to capture the location of an electron using some photography/microscopy you need to use some photons(light particles), when electron gets hit by them, they get activated and change their location, so the captured location is not the original location of electron. We can just find the probability of finding the electron around the nucleus which is the electron density distribution. I assumed electrons as particles here, if they are are considered as waves there is another explanation electrons cannot be at the same place at the same time. A calculation shows that the electron is traveling at about 2,200 kilometers per second. That's less than 1% of the speed of light, but it's fast enough to get it around the Earth in just over 18 seconds.

Coulomb force or more commonly known as electrostatic force The Standard International Unit used to measure electric charge is the Coulomb (abbreviation C). The actual definition of this unit cannot be explained fully until advanced higher. The charge of a proton is equal to e = 1.602x10-19 C. The charge of an electron is the negative of that. Charles-Augustin de Coulomb. 1736 - 1806 

Coulombs Law Increased charge  increased force of attraction Increased distance between charged particles  decreased force of attraction What implications could this have for the chemistry of elements and periodicity ?

https://whitburnscience.wikispaces.com/%28B%29+PERIODICITY

Unit of length 1 meter, symbol m. 1 decimetre, symbol dm 1/10 of a meter 1 centimetre, symbol cm 1/100 of a meter

The picometre (International spelling as used by the International Bureau of Weights and Measures; SI symbol: pm) or picometer(American spelling) is a unit of length in the metric system, equal to one trillionth (i.e., 1/1,000,000,000,000) of a metre, which is the SI base unit of length. It can be written in scientific notation as 1×10−12 m, in engineering notation as 1 E−12 m, and is simply1 m / 1,000,000,000,000. It is also one hundredth of an angstrom, an internationally recognised (but non-SI) unit of length. 1 angstrom = 1.0 × 10-10 metres

Transmission Electron Microscope Transmission electron microscope - The first experimental image of lithium atoms from a transmission electron microscope. Typically micro and nano meter scale.

Lux In just the right light it is possible to perceive Boltwood’s foresight

Microscopy uses the EM spectrum Problem is wavelength, in principle you can't resolve things that are closer together than the wavelength of light.

Micrographia Robert Hooke (1665) “But Nature is not to be limited by our narrow comprehension; future improvements of glasses may yet further enlighten our understanding, and ocular inspection may demonstrate that which as yet we may think too extravagant either to feign or suppose.”

User Operated - CCD Detector ~$200K X-Ray Tube

~$350K Image Plate Curved Image Plate

"Seeing" Individual Molecules, Atoms, and Bonds? Problem:

Electromagnetic Waves What IS light? Electromagnetic Waves

Accelerated Electrons “Scatter” Light direct beam Why don’t protons or other nuclei scatter light? Too heavy!

But a lens for x-rays is hard to come by. By refocussing, a lens can reassemble the information from the scattered wave into an image of the scatterers. But a lens for x-rays is hard to come by.