CHAPTER 6 Elements and the Periodic Table 6.2 Properties of Groups of Elements

2 There are millions and millions of different kinds of matter (compounds) composed of the same 92 elements. These elements are organized in a periodic table. It is called “periodic” because there is a repeating pattern.

3 6.2 Properties of Groups of Elements There are millions and millions of different kinds of matter (compounds) composed of the same 92 elements. These elements are organized in a periodic table. It is called “periodic” because there is a repeating pattern. Elements that belong to the same column have similar chemical properties. Here, we are going to go over these groups of elements

4 6.2 Properties of Groups of Elements Alkali metals

5 6.2 Properties of Groups of Elements Physical properties of Alkali Metals shiny solid at room temperature, malleable, ductile, high melting points, good conductors of heat and electricity. lower densities than other metals, largest atomic radius

6 6.2 Properties of Groups of Elements Alkali metals Electron configuration Alkali metals have a single electron in the highest unfilled energy level.

7 6.2 Properties of Groups of Elements Alkali metals Li + Na + K + Rb + Cs + Fr + Chemical Property – they all form +1 ions. They react explosively with water.

8 6.2 Properties of Groups of Elements Alkali metals 2:1 ratio with oxygen1:1 ratio with chlorine We will see why this happens after we discuss oxygen and chlorine.

9 6.2 Properties of Groups of Elements Alkaline earth metals

Properties of Groups of Elements Physical properties of Alkaline Earth Metals shiny solid at room temperature, malleable, ductile, high melting points, good conductors of heat and electricity. Slightly smaller atomic radius than group 1 elements

Properties of Groups of Elements Electron configuration Alkaline earth metals have two electrons in the highest unfilled energy level. Alkaline earth metals

Properties of Groups of Elements Alkaline earth metals Be 2+ Mg 2+ Ca 2+ Sr 2+ Ba 2+ Ra 2+ Chemical property: forms +2 ions

Properties of Groups of Elements 1:1 ratio with oxygen1:2 ratio with chlorine We will see why this happens after we discuss oxygen and chlorine. Alkaline earth metals

Properties of Groups of Elements Transition metals

Properties of Groups of Elements Physical properties of Transition metals shiny solid or liquid at room temperature, malleable, ductile, high melting points, good conductors of heat and electricity.

Properties of Groups of Elements Transition metals

Properties of Groups of Elements Transition metals Electron configuration Transition metals all have electrons in partly filled d orbitals.

Properties of Groups of Elements Transition metals Bonding properties are complicated. For bonding with oxygen: 2:1 ratio for silver1:1, 2:3, 3:4 ratios for iron

Properties of Groups of Elements Carbon, nitrogen, and oxygen

Properties of Groups of Elements Carbon, nitrogen, oxygen Extremely important elements to be discussed separately

Properties of Groups of Elements Carbon, nitrogen, oxygen The electron structures makes these elements very flexible in their chemistry. Nitrogen and oxygen tend to accept electrons Carbon can accept or donate electrons

Properties of Groups of Elements Example compounds Carbon can bind many elements, including itself. Nitrogen compounds Carbon compounds

Properties of Groups of Elements Halogens

Properties of Groups of Elements Physical properties of Halogens exhibit highly variable physical properties. Halogens range from solid (I 2 ) to liquid (Br 2 ) to gaseous (F 2 and Cl 2 ) at room temperature. Highest electronegativities, smaller atomic radii

Properties of Groups of Elements Halogens Halogens have a single open quantum state in the highest energy p orbital.

Properties of Groups of Elements Halogens F – Cl – Br – I – At – Chemical property: form –1 ions.

Properties of Groups of Elements In their pure forms: Halogens form diatomic molecules (Cl 2, F 2 ) They are highly reactive, and toxic to many organisms. Halogens When combined with a metal: The resulting compound is generally an ionic salt.

Properties of Groups of Elements Noble gases

Properties of Groups of Elements Physical Properties of Noble Gases The noble gases have low boiling points and are all gases at room temperature. These inert gases have high ionization energies and almost no value for electronegativity.

Properties of Groups of Elements The highest energy levels are completely filled. Electrons in completely filled energy levels do not make bonds. Noble gases

Properties of Groups of Elements Noble gases Elements in group 18 are called “noble gases” because they mostly do not chemically bond with any of the other elements.

Properties of Groups of Elements Remember: Electrons are responsible for bonding properties. Bond formation 1 empty quantum state left in the highest unfilled energy level 1 single electron in the highest unfilled energy level

Properties of Groups of Elements 18 electrons like argon 10 electrons like neon By forming the ionic compound sodium chloride, both chloride and sodium ions achieve a noble gas electron structure! Bond formation

Properties of Groups of Elements Bond formation 2 empty quantum states left in the highest unfilled energy level 1 single electron in the highest unfilled energy level Can you form a molecule with hydrogen and oxygen atoms?

Properties of Groups of Elements Bond formation Each hydrogen atom donates one electron to the oxygen atom Oxygen now has 10 electrons, like neon (a noble gas)

Properties of Groups of Elements Elements that belong to the same period in the periodic table have similar chemical properties. This is because they have similar electron configurations, and electrons are responsible for bonding properties. A noble gas electron structure is obtained through bond formation.