Chemistry Class: Element Classification and Properties

Questions and Answers

How many neutrons are in the following isotope: Mg-23?

Name the intermolecular attraction responsible for the unusually high boiling point of water.

hydrogen bonding

Which set of formulas represent one ionic compound and one molecular (covalent) compound?

Cl2 and H2S

BaCl2 and N2O4 (correct)

N2 and SO2

NaOH and BaSO4

Using reference tables S and T, what volume will a 20.0g sample of magnesium (Mg) occupy?

11.5 mL Signup and view all the answers

Isotopes of the same element must also have the same?

atomic number. Signup and view all the answers

Draw a particle diagram of a substance in the solid phase and in the gas phase.

The solid phase has a definite shape and volume, while the gas phase spreads out to fill its container. Signup and view all the answers

The bonds present in carbon monoxide, CO, are?

polar covalent Signup and view all the answers

Water is?

made with polar covalent bonds and is a polar molecule. Signup and view all the answers

Draw the Lewis structure for a sulfur atom and a sulfur ion.

Sulfur atoms have 6 valence electrons, and the ion gains 2, resulting in a structure with 8 valence electrons. Signup and view all the answers

Which particle has a greater mass: electron or neutron?

neutron Signup and view all the answers

This particle diagram contains?

a mixture of a compound and an element Signup and view all the answers

Which of the following is an ionic compound?

CaO Signup and view all the answers

What is the difference between an ionic bond and a covalent bond?

In an ionic bond, valence electrons are transferred, while in a covalent bond, electrons are shared. Signup and view all the answers

How do you tell if a molecule is polar or nonpolar?

Use S.N.A.P.: symmetrical shape = nonpolar, asymmetrical shape = polar. Signup and view all the answers

Draw a particle diagram for a diatomic element.

It will have the same two kinds of atoms bonded together. Signup and view all the answers

Draw a particle diagram for a gas.

Gas particles have high kinetic energy, occupying uniform spaces in their container. Signup and view all the answers

Why do atoms bond?

To become more stable and obtain a stable octet electron configuration. Signup and view all the answers

Draw a graph showing the relationship between pressure and temperature of a gas.

The graph should show that as temperature increases, pressure also increases. Signup and view all the answers

Draw a graph showing the relationship between pressure and volume of a gas.

The graph should illustrate that as pressure increases, volume decreases. Signup and view all the answers

State two important conclusions to Rutherford's gold foil experiment.

The atom is mostly empty space and contains a dense, positive area called the nucleus. Signup and view all the answers

The boiling point of water is higher than the boiling point of alcohol. Why?

Water has stronger intermolecular attractions. Signup and view all the answers

In a phase change diagram, how will you know where a phase change is occurring?

Look at the plateau where temperature remains constant. Signup and view all the answers

When a bond forms between a metal and a nonmetal?

the metal loses valence electrons, gets smaller and positive Signup and view all the answers

Which heat formula would you use for the following question: How much heat is released when 300.0g of water condenses at 100 C?

q = mHf Signup and view all the answers

Which gas law formula would you use to solve the following: Calculate the volume a 5.0 L sample of gas will occupy when the temperature increases from 200K to 400K?

V1 / T1 = V2 / T2 Signup and view all the answers

Study Notes

Element Classification and Properties

Boron (B) is classified as a metalloid, while sulfur (S) and xenon (Xe) are nonmetals, and potassium (K) is a metal.
Strontium (Sr) and barium (Ba) have similar chemical properties due to having the same number of valence electrons, which dictates reactivity.
The periodic table arranges elements according to increasing atomic number, a method established by Henry Mosely after Mendeleev's initial atomic mass arrangement.
Halogens (group 17) have the highest electronegativity among the listed groups, with metals having low electronegativity.

Electron Configuration and Atomic Structure

A correct classification of Ni, Ne, Mg, and Si yields nonmetal, noble gas, metal, and metalloid respectively.
Electronegativity is the measure of an atom's attraction for electrons in a bond, distinguishing it from concepts like ionization energy and atomic radius.
Noble gases in group 18 have a stable electron configuration, adhering to the "octet rule."
An orbital, defined in the wave mechanical model, represents a probability area for finding an electron around the nucleus.

Nucleus and Atomic Mass

The atom's nucleus is positively charged, containing protons and neutrons, with protons contributing to the atom's mass.
Rutherford's gold foil experiment revealed that atoms are mostly empty space with a dense positive nucleus at the center.
To find the average atomic mass of a sample, multiply the mass of each isotope by its percentage and sum the results.

Isotopes and Subatomic Particles

Isotopes like Cl-37 and Cl-34 differ in their number of neutrons while having the same number of protons.
The number of neutrons in an isotope can be calculated by subtracting the atomic number from the atomic mass.
Proton and neutron masses are approximately equal, while an electron's mass is negligible.

Chemical and Physical Changes

Melting is a physical change where bonds remain intact, unlike a chemical change, which alters the molecular structure.
Water's higher boiling point than alcohol is attributed to stronger intermolecular attractions.

Phase Changes and Gas Laws

Gas pressure and temperature have a direct relationship; as temperature rises, gas pressure increases.
An increase in pressure leads to a decrease in gas volume, indicating an indirect relationship.
In phase change diagrams, flat segments indicate changes in state (solid to liquid or liquid to gas), while diagonal segments reflect increases in kinetic energy.

Bonding and Molecular Structure

Ionic bonds involve valence electron transfer from metals to nonmetals, forming positive ions, while covalent bonds involve sharing of electrons.
Polar covalent compounds have asymmetrical shapes and differences in electronegativity, while nonpolar compounds are symmetrical.
Intermolecular forces, like hydrogen bonding, significantly affect boiling points, as seen in water.

Applications in Calculations

The heat released during condensation is calculated using the heat of vaporization, while changes in temperature utilize the specific heat formula.
Gas law calculations depend on the applicable relationships between volume, pressure, and temperature.

Particle Diagrams and Molecular Representation

Diagrams should illustrate the arrangement of molecules in solid and gas phases, reflecting their kinetic energy and spacing.
Diatomic elements consist of two identical atoms and exhibit characteristics of elements rather than compounds.

Summary of Key Concepts

Atoms bond to achieve stability as noble gases do, typically targeting a stable octet.
Understanding intermolecular attractions, electron configurations, and phase changes enhances the comprehension of chemical behavior and properties.

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Description

Test your understanding of element classification, periodic trends, and atomic structure in this quiz based on foundational chemistry concepts. Explore the properties of metals, nonmetals, and metalloids as well as the significance of electronegativity and electron configuration in chemical bonding.