An atom is often referred to as the building block of matter. Atoms have a nucleus surrounded by an electron cloud An atom is often referred to as the building block of matter. Atoms have a nucleus surrounded by an electron cloud Atoms are composed of smaller subatomic particles in an atom. The proton, neutron, and electron. Each element is composed of one type of atom and can not be broken down into a simpler substance
Nucleus - Small, dense, positively charged center of the atom which contains most of the atom’s mass - Nucleus - Small, dense, positively charged center of the atom which contains most of the atom’s mass
- The nucleus contains subatomic particles that have certain characteristics:
- Protons (p+) - positively charged particles in the nucleus of the atom, contribute to the atom’s mass
- Neutrons (no)- particles in the nucleus that have no charge, but contribute to the atom’s mass NEUTRAL
Electron cloud - an area encircling the nucleus where electrons are likely to be found - Electron cloud - an area encircling the nucleus where electrons are likely to be found
- The cloud contains energy levels
- electrons (e-)are negatively charged particles located in specific energy levels
- energy levels completely surround the nucleus
- there is a specific order for the electrons to fill the energy levels
Energy levels completely surround the nucleus - Energy levels completely surround the nucleus
valence electrons are in the outermost energy level and are the electrons involved in bonding - valence electrons are in the outermost energy level and are the electrons involved in bonding
The number of protons in the nucleus is the atomic number of that atom. The number of protons in the nucleus is the atomic number of that atom. The number of protons (+) equals the number of electrons (-) in a neutral atom - mass is reported in the SI units atomic mass units (amu)
- Protons and neutrons each are given an amu of 1
- Electrons have a mass of nearly zero
The mass number of an atom is for a particular isotope of that element The mass number of an atom is for a particular isotope of that element Mass number is the total number of protons and neutrons in the nucleus Example for C-12: - 6 protons + 6 neutrons= 12
- 12 is the mass number for Carbon-12
- *13 is the mass number for Carbon-13 and comes from C-13 having 6 protons and 7 neutrons
Dostları ilə paylaş: |