Periodic Table Properties and trends Periodic Table arrangement

Periodic Table Properties and trends

Periodic Table – arrangement of elements in order of increasing atomic number with the elements having similar properties in vertical columns Groups – vertical columns (v. e. -) Groups are considered “families” since they have similar properties Periods – horizontal rows (shells)

Physical States and Classes of the Elements Majority of the elements are metals. They occupy the entire left side and center of the periodic table. (to the left of the staircase) Nonmetals occupy the upper-right-hand corner. (to the right of the staircase) Metalloids are located along the boundary(staircase) between metals and nonmetals

Metals- located to the left of the staircase Metals elements that have luster, conduct heat and electricity, and usually bend without breaking.

Transition Metals The elements in the middle of the periodic table are called the transition elements. All transition elements are metals. Many transition metals can have more than one charge (from the possible loss of electrons)

Non Metals Although the majority of the elements in the periodic table are metals, many nonmetals are abundant in nature Most nonmetals don’t conduct electricity, are much poorer conductors of heat than metals, brittle when solid. Many are gases at room temperature; those that are solids lack the luster of metals.

Metalloids have some chemical and physical properties of metals and other properties of nonmetals. In the periodic table, the metalloids lie along the border between metals and nonmetals.

Periodic Trends are trends that represent an increase or a decrease occur across the periodic table and down the periodic table LOOK UP EACH TREND AND EXPLAIN IN DEPTH THE cause of the trend. Write any important information that explains why the trend exists They include: atomic radius, Ionization energy, electronegativity, ionic radius

Atomic Radius – size of the atom

Atomic radius The distance from the outer edge of the electron cloud to the nucleus. The radius increases as the principle quantum number increases. So elements increase going from top to bottom. As the period is increased, radius increases.

Atomic radius As you move from left to right across the period things change. The # of protons in the nucleus increases. “higher effective nuclear charge. " • there is a stronger force of attraction pulling the electrons closer to the nucleus resulting in a smaller atomic radius. Right to left and top to bottom is the direction of increased atomic radius

Ionization Energy Ionization energy – the ability to pull off 1 electron Metals- don’t like electrons lose them easily (low energy) Nonmetals – like electrons, want to keep them, require energy to remove them. (higher energy)

Ionization energy-The energy required to remove the most loosely held electron from an element. Large radii elements lose electrons easily Small radii elements require energy to remove electrons.

Ionization Energy cont. Moving down a group means the electrons are further from the nucleus and easier to remove the outermost electron. As you move to the top, and across a period, ionization energy increases because the atomic radius decreases. Meaning the atom is smaller so the outer electrons are closer to the nucleus therefore they are more strongly attracted to the center.

Electro negativity – a chemical property that describes the tendency or ability of an atom to attract electrons from another atom

Ionic radius The more (+) charge an ion has the greater the ability to attract electrons to itself and is therefore smaller. The more (–) charge an ion has the more electrons it has pulling away from the nucleus and therefore they are larger.

Ionic Radius When you talk about ionic radius, you are comparing an atom and its ion When an atom has a negative charge, you have added electrons Which makes it bigger For example, which will be larger: Cl or Cl-1

Ionic Radius When an atom has a positive charge, you have taken away electrons Which makes it smaller For example, which will be larger: Na or Na+1