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