Test 4 & 5 Science

An element has 35 protons and its mass number is 80. How many neutrons does it have?

45 neutrons

.Mendeleev gave the name eka-aluminum to a(an) unknown element he predicted would have properties similar to

Aluminum

Moving from left to right across a row of the periodic table, what value increases by exactly one from element to element?

Atomic number

In the nucleus of a neutral atom, there are 16 protons and 18 neutrons. What are the atomic number ,mass number , and number of electrons?

Atomic number is 16 Mass number is 34 There are 16 electrons

The Greek philosopher Democritus coined what word for a tiny piece of matter that cannot be divided?

Atomos

Describe the arrangement of electrons in Bohr's atomic model.

Electrons travel around the nucleus in fixed energy levels with energies that vary from level to level.

An atom where an electron moves to a higher energy level is in its ground state.

FALSE

Which halogen is most likely to react?

Flourine

Who provided evidence for the existence of a nucleus in an atom?

Rutherford

What is the difference between an atom in the ground state and an atom in an excited state?

The atom in an excited state has more energy and is less stable than the atom in the ground state.

What can you assume has happened if an electron moves to a higher energy level?

The electron has gained energy (absorption)

What does the electron cloud model describe?

The most likely locations of electrons in atoms

True or False The nuclei of isotopes contain different numbers of neutrons.

True

The atomic mass of an element is

a weighted average of the masses of an element's isotopes.

Which statement about electrons and atomic orbitals is NOT true? a. An electron has the same amount of energy in all orbitals. b. An orbital can contain a maximum of two electrons. c. An electron cloud represents all the orbitals in an atom. d. An atom's lowest energy level has only one orbital.

a. An electron has the same amount of energy in all orbitals.

According to John Dalton's observations, when elements combine in a compound, the ratio of their masses is _______ the _________.

always same

The unit for atomic mass is

amu

Mendeleev arranged the known chemical elements in a table according to increasing

atomic mass

One twelfth the mass of a carbon-12 atom is used to define a(an)

atomic mass unit

The number of protons in one atom of an element is that element's

atomic number

Which of the following is NOT part of John Dalton's atomic theory? a. All elements are composed of atoms. b. All atoms of the same element have the same mass. c. Atoms contain subatomic particles. d. A compound contains atoms of more than one element.

c. Atoms contain subatomic particles.

Which statement is true about oxygen-17 and oxygen-18? a. They do not have the same number of protons. b. Their atoms have an identical mass. c. They are isotopes of oxygen. d. The have the same mass number.

c. They are isotopes of oxygen.

Which of the following most accurately represents John Dalton's model of the atom? A. a tiny, solid sphere with an unpredictable mass for a given element B. a hollow sphere with a dense nucleus C. a tiny, solid sphere with a predictable mass for a given element D. a sphere that is hollow throughout

c. a tiny, solid sphere with a predictable mass for a given element

The usefulness of Mendeleev's periodic table was confirmed by a. the discovery of subatomic particles. b. its immediate acceptance by other scientists. c. the discovery of elements with predicted properties. d. the discovery of the nucleus.

c. the discovery of elements with predicted properties.

Which statement about subatomic particles is true? a. Protons, neutrons, and electrons all have about the same mass. b. Unlike protons or neutrons, electrons have no mass. c. Neutrons have no charge and no mass. d. An electron has far less mass than either a proton or neutron.

d. An electron has far less mass than either a proton or neutron.

Which statement about subatomic particles is NOT true? a. Protons and neutrons have almost the same mass. b. Protons and electrons have opposite charges. c. Unlike protons and electrons, neutrons have no charge. d. Protons and neutrons have the same charge.

d. Protons and neutrons have the same charge.

Suppose an atom has a mass number of 23. Which statement is true beyond any doubt? a. The atom has an odd number of neutrons. b. The atomic number is less than 11. c. The atom is not an isotope. d. The number of protons in the nucleus does not equal the number of neutrons.

d. The number of protons in the nucleus does not equal the number of neutrons.

Which subatomic particle has a negative charge?

electrons

In an atomic model that includes a nucleus, the positive charge is located...

in the center of an atom

In Niels Bohr's model of the atom, electrons move

like planets orbiting the sun

The glowing of a neon light is caused by electrons emitting energy as they

move from higher to lower energy levels

J. J. Thomson's experiments provided evidence that an atom contains ____________ charged particles.

negatively

Group 7A of the periodic table contains the most reactive _____________.

nonmetals

What number is unique for any given element?

number of protons

What do scientists use to predict the locations of electrons in atoms?

probability

Democritus thought that matter was made of tiny particles...

that could not be divided

The tendency of an element to react is closely related to

the number of valence electrons in atoms of the element.