If you draw a straight line through the centre of a circle, that’s called the diameter. You’ve probably learned from math class that a circle has a radius. You’re about to learn how to make four important predictions about atoms – atomic radius, ionisation energy, electron affinity, and electronegativity – just by judging how far “up or down” and “left to right” the element is in the Table. A vertical line of elements going up and down the table is called a column, or a group. Remember from your class that a horizontal line of elements going across the table is called a row, or a period. We’re going to give you some basic “left to right” and “up to down” rules. That’s what we’re going to be talking about today. Chemists could use these trends to make instant predictions about an element, without having to use any math at all. When some of the pioneers of chemistry – Dimitri Mendeleev, Antoine Lavosier, and others – put together the puzzle pieces of the different elements, they intentionally arranged the elements table into its current form so that trends would start to pop out. You don’t even have to pay attention to the numbers! All you have to do is locate an element on the Periodic Table, and the location alone is going to give you a lot of useful information. Don’t worry! With this guide you’re reading, you don’t have to worry about the atomic weights. While all of the information is really useful, it can sometimes be hard to keep everything straight. All the strange combination of letters, all the numbers – it can be very confusing. It might be hanging from a wall on a poster, or inside the back cover of your textbook. If you’re taking a chemistry class or even a general science class, chances are pretty good that you have a copy of the Periodic Table of Elements.
0 Comments
Leave a Reply. |