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Physical science Chapter 4
Terms in this set (54)
who developed an atomic theory?
1) atoms could not be divided
2) all atoms of a given elements were exactly alike
3) atoms of different elements could join to form compounds
Dalton's atomic theory
what is Dalton's theory considered?
the foundation for modern atomic theory
______ are the building blocks of molecules
Can atoms join?
an atom's central region which is made up of protons and neutrons
a subatomic particle that has a positive charge and that is found in the nucleus of an atom
a subatomic particle that has no charge and that is found in the nucleus of an atom
a subatomic particle that has a negative charge
what is unique for each element?
the number of protons and electrons
what do unreacted atoms have?
no overall charge
why do atoms not have a charge?
because they have an equal number of protons and electrons whose charges exactly cancel
what does Bohr's model compare?
electrons to planets
in Bohr's model, what does each electron have, and how is it determined?
they have a certain energy that is determined by its path around the nucleus (path defines the electron's energy level)
what do electrons act more like?
what cannot be determined about electrons?
its exact position
what exist in energy levels?
a region in an atom where there is a high probability of finding electrons
where are electrons found?
in orbitals within energy levels
an electron that is found in the outermost shell of an atom and that determines the atom's chemical properties
the periodic table groups ______ elements together
what is the order of the periodic table based on?
the number of protons an atom of that element has in its nucleus
what does the periodic table help determine?
what do elements in the same group have?
why are atoms of group 1 elements reactive?
outermost energy level contains only 1 electron (has to gain an electron)
when an atom loses or gains valence electrons so they can have a full outermost s and/or p orbital
an atom or group of atoms that has lost or gained one or more electrons and has a negative or positive charge
What does the atomic number equal?
the number of protons, and electrons
the number of protons in the nucleus of an atom
the sum of the numbers of protons and neutrons in the nucleus of an atom
atoms of the _____ element have the same ______ _____, but they have different _____ _____ depending on how many neutrons each atom has
same, atomic number, mass number
Isotopes of an element have a different number of ______
an atom that has the same number of protons as other atoms of the same element do but has a different number of neutrons
a unit of mass that describes the mass of an atom or molecule. 1/12 of the mass of carbon
atomic mass unit (amu)
How are metals classified?
metals, nonmetals, semiconductors
an element that is shiny and conducts heat and electricity well
an element that conducts heat and electricity poorly
an element or compound that conducts electric current better than an insulator but not as well as a conductor does
one of the elements of Group 1 of the periodic table
what is another name for semiconductors?
how many different kind of metals are there?
why are alkali metals very reactive?
one valence electron that can be removed to form a positive ion
one of the elements of Group 2 of the periodic table
alkaline earth metals
are alkaline earth metals more reactive than alkali metals?
one of the elements of Groups 3-12 of the periodic table
_____ and _______ are synthetic elements
Where are nonmetals found? which element is the one exception?
on the right side except for Hydrogen
Which classification of metals are plentiful on earth?
What are the most plentiful gases in the air? Which classification are the?
oxygen and nitrogen, non metals
one of the elements of group 17 of the periodic table
A halogen that protects you from harmful bacteria
an nonreactive element of Group 18 of the periodic table
What is different about noble gases from the other elements?
they exist as a single atom
What is the most familiar semiconductor?