Module 3 Test Flashcards
Who was the first to argue that all matter was made from indivisible particles called atoms?
Democritus
What is a unique characteristic for each element?
the number of protons
What does the Law of Conservation state?
matter cannot be created or destroyed, but matter can change forms
How do you find the atomic number?
It is the number of protons.
Describe John Dalton’s atomic theory
all element are composed of atoms, all atoms of the same element have the same mass, compounds are made of atoms of more than one element.
An atom’s lowest energy level has only ___ orbital
one
How do you calculate the atomic mass?
Add the number of protons and the number of neutrons.
Which group of elements on the periodic table are the most reactive?
Group 1A elements
Describe some statements about subatomic particles.
an electron has far less mass than either a proton or neutron, protons and neutrons have almost the same mass, protons and electrons have opposite charges
elements with 7 valence electrons and in Group 7A
halogen
In Rutherford’s atomic model with a nucleus, the positive change is
concentrated in the center of the atom
An orbital can contain a maximum of ___ electrons.
two
An electron has ___ energy in every orbital.
more
elements with 1 electron and in Group 1A
alkali metals
What is true about the difference between an atom in the ground state and an atom in an excited state?
An atom in an excited state has more energy than an atom in the ground state, but it is less stable.
An ___ ___ represents all the orbitals in an atom.
electron cloud
The number of electrons in the orbitals ___ the number of protons in the nucleus
equals
What are the rows and columns of the periodic table called?
rows are called periods and columns are called groups
What subatomic particle has a negative charge?
the electron has a negative charge
The nuclei of isotopes contain different numbers of ___.
neutrons
What determines an elements chemical properties?
the number of valence electrons
