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