Chemistry Unit 2 Part 2

columns on the periodic table are called ______, and rows on the periodic table are called ______

groups, periods

The 7 periods on the periodic table correspond to the ____ where the electrons can exist in an atom.

energy levels/shells

Why do elements in the same group have similar properties?

They have similar physical and chemical properties because of the similar valence electron configurations. The properties of an element are determined by the valence electrons.

How is the periodic table arranged and why?

Elements on the periodic table are arranged in order of increasing atomic number and a periodic repetition of physical and chemical properties

Define valence electrons

the electrons in the highest-filled energy level or outermost shell of an atom

what are the three main classes of elements

metals: lustrous (shiny), malleable, ductile, good conductors of metal and heat

Non-metals: brittle, powdery solids or gases/liquids at room temp, poor conductors of heat and electricity

metalloids: semiconductors of electricity

   boron, antimony, silicon, arsenic

These elements share similar properties because they are all metalloids.

hydrogen, oxygen, fluorine, nitrogen

These elements share similar properties because they are all nonmetals. They are also all gases at room temperature.

beryllium, boron, carbon, nitrogen

Although these elements are in the same period, they are metals/metalloids/nonmetals, so they do not share similar properties

Which of the following elements would have the most similar properties as Fe? Explain your reasoning.

Fe is a transition metal. Na and Zn are both metals, but since Zn is also a transition metal, Fe and Zn would have the most similar properties.

Which of the following elements would have the most similar properties as Cl? Explain your reasoning.

Cl is a nonmetal and a halogen. Since Br is also a nonmetal and a halogen (they are in the same group), Br and Cl would have the most similar properties.

An unknown element is lustrous and ductile. It is a good conductor of heat and electricity. This element is most likely

 Most metals, including transition metals, have these characteristics. Cu is a metal and in the transition metal category on the periodic table.

An unknown element is inert and non-reactive. This element is most likely

Noble gases in Group 8A are inert and non-reactive. Ne is in 8A.

An unknown element is fairly reactive and used in fireworks and flares. This element is most likely

Ba because it is very reactive

Compare and contrast alkali metals and transition metals.

Alkali metals and transition metals are both classified as metals. Therefore, they are both good conductors of heat and electricity and are lustrous. Other similarities would include properties, such as tensile strength, malleability, and ductility. They differ in the sense that alkali metals are highly reactive, especially with water, and therefore, do not exist freely in nature. Transition metals are less reactive and exist freely in nature

Compare and contrast lanthanides and actinides.

both heavy metals in the inner transition metals section of the periodic table. Lanthanides are called “rare earth metals”, whereas actinides are mostly radioactive and synthetic/man-made.

Define atomic radius.

The distance between the center of the nucleus of an atom and the edge of an atom

Atomic radius ___ left to right across a period and ____ down a group on the periodic table

decreases, increases

 Define ionization energy.

Ionization energy is the energy required to remove an electron from an atom.

 Ionization energy left to right across a period and down a group on the periodic table.

increases, decreases

Define electronegativity

Electronegativity is the ability for an atom to attract electrons in a compound.

Electronegativity ____ left to right across a period and ___ down a group on the periodic table.

increases, decreases

How many valence electrons do halogens have?

7

Why does the electronegativity increase from left to right across a period?

 The positively charged protons in the nucleus attract the negatively charged electrons. As the number of protons in the nucleus increases, the electronegativity or attraction will increase.

Why does electronegativity decrease down a group?

The electrons are further away from the nucleus, so the nucleus does not have as strong of a pull on the electrons.

Akali metals

(1A) extremely reactive, react in water, stored in oil. Not fund free in nature, soft metals, shiny lustrous

Alkaline Earth Metals

(2A) Less reactive than alkali metals, but still too reactive to be found free in nature, used in flares and fireworks

Halogens

(7A) Most reactive non-metals

Noble Gases

(8A) Non-reactive, have 8 valence electrons

Transition Metals

Good conductors of heat and electricity, ductile, malleable, lustrous, less reactive than alkali and alkaline, exist as free elements

Lanthanides

rare earth metals

Actinides

They are all radioactive