Chapter 12

• Periods in the periodic table are represented by rows of elements.
• Groups in the periodic table are represented by columns of elements.
• Representative elements in the periodic table are all elements in Groups 1A to 8A.
• Transmission elements in the periodic table are Group 1B to 8B.
• Elements in the same group, such as Group 1A, have similar properties.
• There are 118 known elements in the periodic table.
• Alkali Metals, which are in Group 1A, are the most reactive elements in the periodic table.
• Alkaline Earth Metals, which are in Group 2A, are harder and less reactive than alkali metals.
• Boron Group, which is in Group 3A, is the topmost element of the group and is moderately reactive and radioactive.
• Carbon Group, which is in Group 4A, is a poor conductor of heat and electricity, similar to wood.
• Nitrogen Group, which is in Group 5A, or pictogens, is a poor conductor of heat and electricity, similar to wood.
• Oxygen Group, which is in Group 6A, or chalcogens, is a poor conductor of heat and electricity, similar to wood.
• Halogens, which are in Group 7A, are highly reactive to alkali metals and form salts.
• Noble Gases, which are in Group 8A, also called inner gases and are the least chemically reactive.
• Nonmetals are poor conductors of heat and electricity, similar to wood.
• Hays-McDaniel line in the periodic table separates properties that are intermediate of metals and nonmetals.
• Valence Electrons are the outermost electrons in an atom involved in chemical reaction.
• Orbital in the periodic table is the region of space that accommodates electrons within an atom.
• Xenon arc lamp in the periodic table is a lamp filled with xenon gas at high pressure.