Physical Science Mod 2 Group ?s (Ch 12)

What is the difference between a physical model and a conceptual model?

A physical model is used for something visible, which replicates it at a more convenient scale. A conceptual model is used for something invisible that can not be put to scale.

Consider these atoms: helium, He; aluminum, Al; and argon, Ar. Rank them, from smallest to largest, in terms of A-size, B-number of protons in the nucleus, and C-number of electrons.

A: He, Ar, Al B: He, Al, Ar C: He, Al, Ar

Distinguish between an atom and an element.

An atom is the smallest unit that makes up matter. It is submicroscopic. An element has only one type of atom. It is macroscopic.

Distinguish between atomic number and mass number.

Atomic number is the number of protons in an atom of an element. Mass number is the total number of protons and neutrons (nucleons).

Use the shell model to explain why a lithium atom, Li, is larger than a beryllium atom, Be.

Be is more squeezed in, so it is smaller. Its electrons have a stronger attraction to its nucleons.

The element bromine, Br (atomic number 35), has two major isotopes of similar abundance, both around 50 percent. The atomic mass of bromine is reported in the periodic table as 79.904 atomic mass units. Choose the most likely set of mass numbers for these two bromine isotopes.

Br-79, Br-81

Consider these atoms: helium, He; chlorine, Cl; and argon, Ar. Rank them in terms of their atomic number from smallest to largest.

He, Cl, Ar

Use the shell model to explain why a potassium atom, K, is larger than a sodium atom, Na.

It is larger because it has an additional orbital (shell).

Neon, Ne (atomic number 10) cannot attract any additional electrons. Why?

Its outer shell is full. It is an inert gas (noble gas)

Distinguish between mass number and atomic mass.

Mass number is the number of nucleons. Atomic mass is the total mass of an atom in amu.

Rank these atoms in order of the number of electrons they tend to lose, from fewest to most: sodium, Na; magnesium, Mg; and aluminum, Al.

Na, Mg, Al

What is the relationship between the maximum number of electrons each shell can hold and the number of elements in each period of the periodic table?

The maximum number of electrons corresponds (is the same as) to the number of elements in each period. Ex: period 1 has 2 elements with a maximum number of 2 electrons in shell 1

Does the periodic table explain the shell model, or does the shell model explain the periodic table?

The shell model helps us understand the periodic table.

If two protons and two neutrons are removed from the nucleus of an oxygen-16 atom, a nucleus of which element remains?

carbon-12

Consider three 1-gram samples of matter: carbon-12, carbon-13, and uranium-238. Rank them in terms of how many atoms they have, from most to least.

carbon-12, carbon-13, and uranium-238

Rank the three subatomic particles in order of increasing mass

electron, proton, neutron

Are most elements metallic or nonmetallic?

metallic

Which electrons are most responsible for the properties of an atom?

valence electrons