Chemistry
Which two particles make up most of the mass of hydrogen-2 atom?
Proton and Neutron
Which two particles each have a mass approximately equal to one atomic mass unit?
Proton and neutron
Which subatomic particles are located in the nucleus of a neon atom?
Protons and neutrons
Adams of 16O, 17O, 18O have the same number of
Protons but different number of neutrons
Which electronic configuration represents an Atom of aluminum and excited state
2-7-4
Which electron configuration should represent a Strontium atom in an excited state
2-8-18-7-3
What is the electron configuration of a sulfur atom in the ground state
2-8-6
Which atoms are isotopes of the same element
24/12X and 25/12X
A 100.00-gram sample of naturally occurring boron contains 19.78 grams of boron-10 (atomic mass=10.01 atomic mass units) and 80.22grams of boron-11 (atomic mass 11.01 atomic mass units). Which numerical setup can be used to determine the atomic mass of naturally occurring boron?
(0.1978)(10.01)+(0.8022)(11.01)
What is the total charge of the nucleus of a carbon Atom
+6
The atomic mass of an ATom is measured in atomic mass units. this unit is based on
12C
Which isotopic nation represent an Atom of a carbon-14
14/6 C
An atom of 40/80 Ar has a nucleus that contains a total of
18 protons
Which principal energy level can hold a maximum of 18 electrons
3
A sample of element X contains 90. Percent 35X Atoms 8.0% 37X Atoms, and 2.0 percent 38X atoms. The average isotopic mass is closet to
35
What is the structure of a krypton-85 atom?
36 electrons 36 protons and 49 neutrons
Which two nuclides are isotopes of the same element?
39/19K and 42/19K
An atom of bromine is in the ground state. The outermost electrons are in principle energy level
4
What is the total number of neutrons in the Atom Li?
4
But atomic mass of element a is 63.6 atomic mass units the only naturally occurring isotopes of element A are A-63 and A-65. The percent abundances and naturally occurring sample of element A are closest to
69% A-63 and 31%A-65
The average isotopic mass of chlorine is 35.5 which mixture of isotopes (shown as percents) produces this average mass?
75% 35C and 25% 37Cl
What is the total number of electrons in the second energy shell of calcium Atom in the ground state
8
A sample composed only of Atoms having the same atomic number is classified as
A element
What was concluded about the structure of the Atom as a result of the gold foil experiment
A positively charged nucleus surrounded by mostly empty space
The Atomic mass of an element is the weighed average of the
Atomic masses of the naturally occurring isotopes of that element
What is the charge and mass of a proton ?
Charge of +1 and mass of 1 amu
As an electron in a hydrogen Atom moves from the second principal energy level to the first principle energy level,the energy of the atom
Decreases
An atom of oxygen is in the excited state when electrons in the Atom moves from the third shell to the second shell energy is
Emitted by the electron
The modern model of the atom shows that electrons are
Found in regions called orbitals
Which of the group 17 elements listed below has the greatest nuclear charge?
I
How do the energy and the most probable location of an electron in the third shell of an Atom compare to the energy in the most probable location of an electron in the first shell of the same Atom?
In the third shell an electron has more energy and is further away from the nucleus
An electron in and Adam moves from the ground state to the excited state when the energy of the electron
Increases
Which statement best describes the nucleus of an aluminum atom?
It has the a charge of +13 and is surrounded by a total of 13 electrons.
Compared to an electron in the first electron shell of an atom, an electron in the third shell of an Atom has
More energy
Atoms of different isotopes of the same element differ in their total number of
Neutrons
Two Atoms will always have the same atomic number if they have the same
Number of protons
An atom is electrically neutral because the
Number of protons equals the number of electrons
Which sequence represents a correct order of historical developments leading to the modern model of the Atom
The atom is a hard sphere—> most of the atom is empty space—> electrons exist in orbitals outside the nucleus
Experimental evidence indicates that the nucleus of an atom
contains most of the mass of the atom