Atomic Structure Subatomic Particles Parts of an atom

Atomic Structure Subatomic Particles

Parts of an atom All atoms, as far as we know, have 3 parts: ◦ Protons ◦ Neutrons ◦ Electrons The protons and neutrons make up the atom’s nucleus, which is like the nucleus of an animal or plant cell – it’s the most important part, and center. The electrons make up the atom’s electron cloud, which is the outer shell (like a gumball) for the atom.

Charges of particles Protons have a +1 (positive) charge Electrons have a -1 (negative) charge Neutrons have a +0 (neutral) charge Charges are important! When charges on an atom are balanced (the same + as -) the atom is stable It is a source of wonder to figure out why particles with similar charges are not repelling each other all the time, and to find out what happens when they do.

Masses of particles Proton: 1. 67262 x 10^-27 kg Neutron: 1. 67493 x 10^-27 kg Electron: 9. 10939 x 10 -31 kg (1836 times lighter than a proton) Note: ◦ The mass of one atom is mostly in its nucleus ◦ Electrons are really tiny

How the atoms of elements are different Hydrogen: 1 proton, 0 neutrons, 1 electron Helium: 2 protons, 2 neutrons, 2 electrons Carbon: 6 protons, 6 neutrons, 6 electrons Rules: ◦ The atomic number tells you how many protons and electrons a stable atom of that element has. ◦ The neutrons are determined by taking the atomic mass (the decimal at the bottom of the square) and subtracting the atomic number from it. ◦ This makes sense: the atomic mass of an atom is determined by how many protons/neutrons there are. Take away the part of the mass that is protons, you have neutrons left over.

Different elements As you read higher on the periodic table, elements get bigger (literally) They have more protons, neutrons, and electrons