Chemistry regents

Is oxidation the loss or gain of electrons?

Loss

Will oxidation number decrease or increase?

Increase

Are electrons placed on the left or right side of the equation for oxidation?

Right side

Is reduction the loss or gain of electrons?

Gain

Will oxidation number decrease or increase for reduction

Decrease

Are electrons placed on the left or right side of the equation?

Left side

What is one way to identify the redox reaction from a nonredox reaction?

There must be a change in oxidation number and look for an element ---> compound or compound ---> element

In a galvanic cell, what change produces another type of energy?

A chemical change produces electrical energy

What is the function of the salt bridge?

Allows the flow of ions between the half cells

How is table J used to determine which substances oxidized and reduced? And which substance gains or loses electrons?

The higher metal will lose electrons (oxidize)

Lower metal ion will gain electrons (reduce)

Describe the flow of electrons through the wire

Electrons flow from higher to lower metal

At the anode, will the concentration of the ions increase or decrease?

Increase

ex. Zn ---> Zn ^+2 +2e

At the cathode, will the concentration of ions increase or decrease?

Decrease

ex. Cu^+2 +2e ---> Cu

List all factors of oxidation

Loss of e-

Ox # increase

e- on right of equation

Anode

Decrease mass

List all factors of reduction

Gain e-

Ox # decreases

e- on left of equation

Cathode

Increase mass

In a voltaic cell, what are the charges of the anode and cathode?

Anode is NEGATIVE

Cathode is POSITIVE

In an electrolytic cell, what are the charges of the anode and cathode?

Anode is POSITIVE

Cathode is NEGATIVE

How are elements arranged on the periodic table

They are arranged by atomic number

Define atomic number

Atomic number is the amount of protons in the nucleus

Why is the nucleus positively charged?

Because protons are positively charged and in the nucleus, so that means that the nucleus is positively charged

What are elements on the left of the periodic table classified as?

Metals

What are elements on the top right of the periodic table classified as?

Nonmetal

What are the nonmetals on the periodic table?

B, Si, Ge, As, Sb, Te, At

What are the properties of metals?

Luster

Ductile

Malleable

Lose e-

Some react with acids

What are the properties of nonmetals?

Dull

Brittle

Gain e-

What are the properties of semimetals?

They have properties of both metals and nonmetals

Atomic radius

Size of the atom

Decrease across a period

Increase down a group

Metallic properties

Luster, ductile, malleable, lose e-, some react with acids

Decrease across a period

Increase down a group

Ionization energy

The energy required to remove an electron

Increase across a period

Decrease down a group

Electronegativity

One atom's attraction to another atoms valence electrons

Increases across a period

Decreases down a group

Metals lose electrons, which means that the ion is…

Smaller

Nonmetals gain electrons, which means that the ion is…

Larger

Elements within the same group have similar reactivity because they have…

the same amount of valence electrons

P G

Ar Dec Inc

Ie Inc Dec

Mp Dec Inc

En Inc Den

Shells Constant Inc

Common diatomics

Br2, I2, N2, Cl2, H2, O2, F2

Ex. Explain, in terms of electrons, why the ionic radius of a group 2 element is smaller than its atomic radius

Ionic radius is smaller because they are metals which will lose electrons

What do protons and electrons have in common?

They have the same number. For example, a boron atom has 5 protons, which means that it also has 5 electrons

What does it mean when an element is unreactive?

It has a filled outer shell

Traits of an ionic bond

There is a transfer of electrons between METAL and NONMETAL elements

Traits of a covalent bond

There is a share of electrons between ONLY NONMETAL elements

Traits of a metallic bond

Exist between METAL elements

Traits of both ionic and covalent bonds

Exist between the atoms in a polyatomic ion

*B

A

R

F

Break

Absorb

Release

Form

Is bond formation exothermic or endothermic?

Exothermic

F + F ---> F2

Is energy absorbed or released during bond formation?

Released

Is bond breaking exothermic or endothermic?

Endothermic

F2 ---> F + F

Is energy absorbed or released during bond breaking?

Absorbed

Ionic properties "salts"

High melting and boiling point

Many dissolve in water

Conduct electricity when dissolved or as a liquid

Covalent (molecular) properties

Low melting and boiling point (increases as the molecule gets larger)

Does not dissolve in water

Reacts slowly because of strong bonds

Why do atoms transfer and/ or share electrons?

To achieve a noble gas configuration

How many total electrons does hydrogen need

2 electrons

Why will any other element transfer or share electrons?

They do this in order to have 8 electrons

Amount of bonds

C (group 14)- 4

N (group 15)-3

O (group 16)-2

F (group 17)- 1