Tutorial:Basic Chemistry Topics: Difference between revisions

An atom is the smallest unit of matter. Protons, neutron, and electrons, make up the composition of an atom providing its physical features. The common physical features of atoms are used to organize them in the periodic table. Electrons are negatively charged particles that surround the atom’s nucleolus. Protons are positively charged particles and neutrons are uncharged. Both neutrons and protons are located in the central part of the atom known as the nucleus.  

The image above displays Oxygen (O) in its periodic box. The atomic number of oxygen is 8, centered above the single-letter abbreviation of Oxygen. “8” represents the number of protons in the atom’s nucleus. The atomic number is also used to arrange elements in the periodic table. Notice the increasing value of protons in the atoms from left to right. The atomic mass of an element is centered under the single-letter abbreviation of an atom and represents the total weight of the atom. In this case, oxygen has an atomic mass of ~16. The total weight of an atom is the sum of the atoms protons, neutrons and electrons.  

The periodic table is a collaboration of atoms that are arranged according to their common features. Groups are the vertical columns of atoms, and the periods are the horizontal rows. When moving from left to right across the periods (horizontally), there is an increase in electronegativity.  Electronegativity refers to the atoms ability to pull other electrons towards it, increasing it’s density and providing itself with a negative charge. The concept of electronegativity contributes to the polarity of an atom. Polarity is caused by a difference in electronegativity between atoms in a compound and/or the asymmetry of the compounds structure. A compound is nonpolar when the electronegativity of the atoms/functional groups are close or even. The compound is symmetrical and the electrons are not being pulled more in one direction.