Chemistry Unit 3

How many valence electrons does hydrogen (atomic number of 1) have?

1

What are three properties of metals that nonmetals typically do not have?

1-shiny 2-ductile 3-good conductor

How many electrons cant the third shell in an atom hold?

18

What year did Dalton make his contribution?

1808

What year did J.J. Thompson make his contribution?

1897

What year did Rutherford contribute?

1909

What year did Bohr contribute?

1913

How many electrons can the first shell in an atom hold?

2

How many electrons can the second shell in an atom hold?

8

An element has an atomic number of 9 and a mass number of 19. How many protons does this element have?

9

What must happen for an ion to form?

An atom must lose or gain an electron.

Why are Bohr models still useful when predicting the bonding of atoms?

Bohr models show the number of electrons (regular and valence) which helps determine which sort of bond should take place.

What is the difference between Bohr model and Lewis structure?

Bohr shows all electrons and Lewis shows only valence

How is the current model of the atom different from Thomson's and Rutherford's model?

Electrons move within an electron cloud only in the current model of the atom.

Who developed the atomic theory?

John Dalton

Where are metals and nonmetals found on the periodic table?

Metals are found to the left of the zigzag and nonmetals are found to the right of the zigzag.

How does the number of valence electrons of an atom help to determine whether an atom is likely to form bonds?

The number of valence electrons tells how many electrons are in the outermost portion of the electron, helping to determine whether the atom should gain, lose, or share an atom.

metallic bond

a bond formed by the attraction between positively charged metal ions and the electrons around them--weak compared to ionic and covalent

covalent bond

a bond formed when atoms share one or more pairs of electrons

ion

a charged particle that forms when an atom or group of atoms gains or loses one or more electrons

molecule

a group of atoms that are held together by chemical forces

period

a horizontal row of elements in the periodic table

chemical symbol

a one, two, or three letter abbreviation of the name of an element

electron cloud

a region around the nucleus of an atom where electrons are likely to be found

electron

a subatomic particle that has a negative charge

proton

a subatomic particle that has a positive charge and that is located in the nucleus of an atom

neutron

a subatomic particle that has no charge and that is located in the nucleus of an atom

group

a vertical column of elements in the periodic table where elements share chemical properties

Group 1

alkali metals

group 2

alkaline earth metals

periodic table

an arrangement of the elements in order of their atomic numbers such that elements with similar properties fall in the same column, or group

nucleus

an atom's central region, which is made up of protons and neutrons

valence electron

an electron that is found in the outermost shell of an atom and that determines the atom's chemical properties

nonmetal

an element that conducts heat and electricity poorly

metalloid

an element that has properties of both metals and nonmetals

metal

an element that is shiny and that conducts heat and electricity well

chemical bond

an interaction that holds atoms or ions together

What do subatomic particles make up?

atom

What did J.J. Thomson discover?

atoms are made up of smaller parts, found electrons, thought atoms were a positive sphere with electrons mixed throughout

Explain the process of covalent bonding.

atoms bond by sharing valence electrons, resulting in full outermost energy levels of each atom

Where is the nucleus found?

center of the atom

Fluorine has 7 valence electrons. What type of bond is likely to form between two atoms of fluorine?

covalent

What are the physical properties of ionic bonds?

crystal lattice structure, poor electrical conductivity, solubility in water, brittle and hard

Where are electrons found?

electron cloud

What is the current model of an atom?

electrons do not move in circular paths around nucleus, suggests that electrons move within the electron cloud

Explain the mass of electrons compared to neutrons and protons.

electrons have very little mass, takes more that 1800 electrons to equal mass of 1 proton

What did Niels Bohr contribute?

electrons move around the nucleus in circular paths

What things do groups have in common?

elements bond similarly and same number of valence electrons

How is chemical bonding related to the organization of the periodic table?

elements in the same group have the same number of valence electrons and elements close to each other bond similarly

What did Ernest Rutherford contribute?

found that atoms have nucleus surrounded by moving electrons, nucleus made of protons

If the nucleus had the volume of a grape, how big would the mass be?

greater than 9 million metric tons

What are the columns called?

group

Which groups participate in ionic bonding?

groups 1 and 17 as well as groups 2 and 16--metal and nonmetal

Which groups participate in covalent bonding?

groups 13,14,15,16,17--nonmetals

What are the columns and rows of the periodic table called?

groups and periods

group 17

halogen

What is the order of strength for bonds?

ionic, covalent, then metallic

What are the physical properties of covalent bonds?

low solubility, low melting and boiling point, poor electrical conductivity

What is the law conservation of mass/matter?

mass cannot be created or destroyed in ordinary chemical and physical changes

How do you find the number of neutrons in an atom?

mass number-protons=neutrons

Good electrical conductivity is a property of this.

metal

What elements have some properties of metals and some properties of nonmetals?

metalloids

Do noble gases react and bond with others? Why or why not?

no--full set of valence electrons

group 18

noble gases

Where are neutrons found?

nucleus

Where are protons found?

nucleus

What order does the periodic table go in?

number order in regards to atomic number and mass

What are the rows called?

periods

What are some properties of nonmetals?

poor conductors of heat and electricity, dull and brittle

In a neutral atom, the number of electrons is equal to the number of this.

protons

What are some properties of metals?

shiny, ductile, malleable, good conductor of heat

What are some properties of metalloids?

some of both metals and nonmetals

What did John Dalton discover?

stated all matter is made of atoms, atoms cannot be created or destroyed, all atoms of certain element are identical, atoms join with other atoms to make new substances

ionic bond

the attractive force between oppositely charged ions, which form when electrons are transferred from one atom to another--metal to nonmetal

atomic number

the number of protons in the nucleus of an atom

atom

the smallest unit of an element that maintains the properties of that element

mass number

the sum of the numbers of protons and neutrons in the nucleus of an atom

average atomic mass

the weighted average of the masses of all naturally occurring isotopes of an element

groups 3-12

transition metals

Explain the process of ionic bonding.

valence electrons move from the outermost energy level of the metal atom to the outermost energy level of the nonmetal atom, resulting in full outermost shells for both atoms

Explain the density of the nucleus.

volume of nucleus is very small, protons and neutrons are very massive so nucleus is very dense