Year 9 CHEMISTRY REVISION Subatomic particles Protons neutrons

Year 9 CHEMISTRY REVISION

Subatomic particles- Protons, neutrons and electrons. 2 Dan Kelly - Magic of Electrons - PLTW - Atoms

IONS What will cause an atom to become a negative ion? Gaining electrons. Why? Electrons have a negative charge so gaining more electrons will make the ion more negative. A particle with 17 protons, 16 neutrons and 18 electrons, is it an Ion? Why? It has gained an electron. What will its charge be? -1 3 Dan Kelly - Magic of Electrons - PLTW - Atoms

PRACTICE YOU HAVE 10 MINUTES TO COMPLETE TASK 1 IN YOUR REVISION BOOKLET!! 4 Dan Kelly - Magic of Electrons - PLTW - Atoms

Atomic number and number of protons Remember atomic number tells us the number of protons. In a neutral atom what does this equal to? The number of electrons. Why? The protons are positively charged and the electrons are negatively charged. In a neutral atom the positive and negative charges must balance. 5 Dan Kelly - Magic of Electrons - PLTW - Atoms

So if we have the atomic number what information about the atom do we have? The number of protons and the number of electrons. So if we have the atomic number can we draw the electron shell diagram and therefore write the electron configuration? YES! Draw the shell diagram and write the configuration for a magnesium atom with the atomic number 12. 6 Dan Kelly - Magic of Electrons - PLTW - Atoms

PRACTICE YOU HAVE 10 MINUTES TO COMPLETE TASK 2 IN YOUR REVISION BOOKLET!! 7 Dan Kelly - Magic of Electrons - PLTW - Atoms

Metals What is an allotrope? Each of two or more different physical forms in which an element can exist. Examples- Graphite, charcoal, and diamond are allotropes of carbon. What is an alloy? An alloy is a metal (known as the base metal) combined with small amounts of another element. Examples- Steel, Brass. 8 Dan Kelly - Magic of Electrons - PLTW - Atoms