Test Q Flashcards
(36 cards)
How many electrons are in the highest occupied energy level of atoms in group 5a?
5 electrons
In 1829, the German chemist J.R. Dobereiner published a classification system in which elements were put into groups their properties, how many elements did he put into each of his groups?
He put them into a triad - 3 elements
Which group of elements are known as the Alkali metals?
Group 1A
Which of the following factors contributes in the increase of ionization energy from left to right in a period?
An increase of the number of protons
Who first suggested the idea of atoms
Democritus
What discovery did J.J. Thompson make that improved upon Dalton’s theory?
Atoms contain tiny, negatively charged electrons
What is true about subatomic particles?
The mass of a neutron nearly equals the mass of a proton
What was originally a tenet of Dalton’s theory but had to be revised about a century ago?
Atoms are tiny indivisible particles
All atoms are:
Neutral, with the number of protons equaling the number of electrons
The atomic number of an element is the total number of which particles in the nucleus?
Protons
The sum of the protons and neutrons in an atom equals the
Mass number
Isotopes of the same elements have different
Numbers of neutrons
How many protons, electrons, and neutrons does an atom with the atomic number 50 and mass number of 125 contain?
Protons : 50
Electrons: 50
Neutrons : 75
What unit is used to measure weighted average atomic mass
Amu
How does the energy of an electron change when the electron moves closer to the nucleus?
It decreases
Why do chemists use relative masses of atoms compared to a reference isotope rather than the actual masses of atoms ?
The actual masses of atoms ar very small and difficult to work with
The principal quantum number indicates what property of an electron?
Energy level
How many sublevels are inter second principle energy level
2
What is the maximum number of electrons in the second principle energy level
8
What types of atomic orbitals are in the third principle energy level
S , p, and d only
According to the aufbau principle
Electrons enter orbitals of the lowest energy first
How many unpaired electrons are in a sulfur atom, which has an atomic number of 16?
2
What idea did Dalton’s atomic theory include?
Atoms of the same element are always identical
The nucleus of an atom is
The central core and is composed of protons and neutrons
