Chemistry Chapter 4 Review

How do alkali metals differ from alkaline earth metals?

Alkali metals are more reactive. Alkaline earth metals are harder, denser, and stronger than alkali metals and have higher melting points.

What is the reason for the way properties vary as you go down the periodic table?

The pull of the nucleus decreases as you go down due to electron shielding.

What is the reason for the way properties vary as you go across the periodic table?

The pull of the nucleus increases as you move across.

Give the group number of the following families of elements: a. alkali metals b. alkaline earth metals c. halogens d. noble gases

a. group 1 b. group 2 c. group 17 d. group 18

Define the property and identify how it varies across a period and down a group. Nonmetallic properties

poor conductors, low luster (dull), low malleability (brittle), low ductility (brittle), gain electrons (- ion), gas/solid (except for BR) trend across: increase trend down: decrease

What is produced when halogens combine with alkali metals?

salts (ionic compounds)-also called halides

Define the property and identify how it varies across a period and down a group. Ionic radius

size of the ion relative or compared to the size of its neutral parent atom trend across: decreases trend down: increases

Define the property and identify how it varies across a period and down a group. Ionization energy

the amount of energy needed to remove an outer electron from an atom or ion in its ground state in the gas phase measured in kilojoules per mole (KJ/mole) trend across: increases trend down: decreases

"Who am I?" Write the symbol of the element being described, or indicate the family by name or group number. 1) The halogen with the largest radius. 2) The lanthanide with the smallest electronegativity. 3) The FAMILY that forms a +1 ion. 4) The most reactive nonmetal. 5) The element in the 4th period with the lowest ionization energy. 6) The element in group 2 with the smallest ionic radius. 7) The most metallic element. 8) The alkali metal with the smallest atomic radius. 9) The least metallic member of the carbon family. 10) The element in the 3rd period that has the greatest affinity for electrons. (The most negative value)

1) AT 2) La 3) alkali metals 4) F 5) K 6) Be 7) Fr 8) Li 9) Sn/C 10) Cl

What groups make up the main group elements?

1,2,13,14,15,16,17,18 s and p blocks-representative elements

What is a nuclear reaction?

A nuclear reaction is a reaction in which the composition of the nucleus of an atom is changed (protons and neutrons are changed). All elements are produced as a result of nuclear reactions.

What is a synthetic or artificial element?

A synthetic element is an element produced by the fusion of atomic nuclei in particle accelerators under conditions of extremely high velocity (high kinetic energy)

What is a transmutation?

A transmutation is the process by which a nucleus is changed, specifically by radioactive disintegration or bombardment of other particles. Synthetic or artificial elements are produced as a result of transmutations.

Why is hydrogen placed in a group by itself?

Does not behave like any other element. Very reactive. Most common element in the Universe. Rare on Earth, since it can escape into space. Component of all hydrocarbons and other molecules essential to life. Forms a +1 ion Nonmetal Very Reactive

What is unusual about the way electron affinity values change as you go across or down the periodic table? Why do these values change as they do?

Electron affinity increases (gets more negative) as you move across a period and decreases (gets less negative or more positive) as you move down a group. Electron affinity is the energy released when an electron is added to an atom or group of atoms in the gas phase. A negative value means energy is released. The atom becomes more stable. A positive value means energy is absorbed. The atom becomes less stable. sign refers to energy released (-) or absorbed (+)

Define the term electron shielding.

Electron shielding is the reduction in the attractive force between the positive nucleus and the negative outermost electrons due to the addition of energy levels thereby creating a shield of inner electrons.

What do elements in a group have in common?

Elements in a group have the same valence or outer electron configuration.

What do elements in a period have in common?

Elements in a period have the same core or inner electron configuration.

When an atom gains an electron, what happen to its size? What is its charge?

It becomes larger because the nucleus is pulling on more electrons and cannot pull the remaining electrons in tighter. Called an anion and has a negative charge.

When an atom loses an electron, what happens to its size? What is its charge?

It becomes smaller because the nucleus is pulling on fewer electrons and can pull them in tighter. Called a cation and has a positive charge.

Define what is meant by malleability and ductility.

Malleability is the ability to be hammered or rolled into sheets. Ductility is the ability to be pulled into thin wires.

What is the difference between a metal and a nonmetal?

Metals are good cconductors of electricity and all are solids at room temperature, except Mercury. (lose electrons) Nonmetals are poor conductors of electricity. Most are gases at room temperature, but there are also some solids and liquids. (gain electrons) generally opposite properties

Identify the one property that all metals share.

Metals are good conductors.

What properties do alkali metals have in common?

Most reactive group of metals. One electron in their valence shell or outermost energy level. Form +1 ions. Excellent conductors of electricity. Soft and easy to cut. Form salts

What properties do the halogens have in common?

Most reactive group of nonmetals. Seven electrons in their valence shell or outermost energy level. Form -1 ions. React with most metals to form salts

What property do noble gases share? How does this property relate to the electron configuration of the noble gases?

Noble gases are unreactive (inert). They have 8 electrons in their valence shell or outermost energy level (stable octet).

Describe two processes that scientists use to create synthetic or artificial elements.

Particle accelerators use magnetic and pulsed electric fields to accelerate charged particles (ions) to high speeds. Cyclotron-Ions are accelerated and collide with stationary nuclei to produce lighter (of the artificial elements) elements. Synchrotron-Heavy ions are accelerated in opposite directions and collide with one another to produce heavier (of the artificial elements) elements.

State the periodic law.

Periodic law states that the physical and chemical properties of elements are periodic functions of their atomic numbers.

What is a naturally occurring element? Where are these elements located in the periodic table?

Produced by the fusion of atomic nuclei in stars under conditions of extreme heat and pressure. This results in larger atoms spread across the Universe following the explosion of giant red stars and supernovae. Not all are found on Earth. They developed from hydrogen following the Big Bang. Approximately 93, periods 1-6 mostly

What properties do alkaline earth metals have in common?

Reactive, but less so than alkali metals. Two electrons in their valence shell or outermost energy level. Form +2 ions. Harder, denser and stronger than alkali metals. Higher melting points than alkali metals Form salts

Which elements are considered the most stable? Why?

The noble gases because they have a full valence shell (stable octet).

Why are elements with atomic numbers greater than 92 referred to as transuranium elements?

They come after Uranium, which is atomic number 92

Why are the nuclear configurations of actinides more important than their electron configurations?

They have an unstable nuclear arrangement, which makes them radioactive. They are characterized by radioactivity.

Explain what transition metals have in common with respect to their electron configurations.

Transition metals have d and f electrons.

What properties do noble gases have in common?

Unreactive (inert). Eight electrons in their valence shell or outermost energy level (stable octet) zero electronegativity

Define the property and identify how it varies across a period and down a group. Metallic properties

good conductor, high luster (shiny), high malleability (soft), high ductility (soft), loses electrons (+ ion), solid (except Hg) trend across: decrease trend down: increase

How and where were the naturally occurring elements created?

in the stars under extreme heat and pressure

What is the name of the elements located between the metals and non-metals in the periodic table?

metalloids (B, Si, As, Te, Ge, Sb)

Define the property and identify how it varies across a period and down a group. Atomic Radius (Bond radius, covalent atomic radius)

one half the distance between the nuclei of two like atom bonded in the solid state and measure in angstroms (size of atom) trend across: decreases trend down: increases

Define the property and identify how it varies across a period and down a group. Electron affinity

the energy released when an electron is added to an atom or group of atoms in the gas phase measured in kilojoules per mole trend across: increases (gets more negative) trend down: decreases (gets less negative)

Define the property and identify how it varies across a period and down a group. Electronegativity

the tendency of an atom to attract bonding electrons to itself, when it bonds with another atom measured on the Pauling scale from 0-4 (4 being the most electronegative) trend across: increases trend down: decreases