5.2 The Modern Periodic Table Questions

How many octaves are visible on the keyboard?

3

What is an atomic mass unit?

A unit of measurement used to weigh atoms that is one twelfth of the mass of a carbon-12 atom

What major change occurs as you move from left to right across the periodic table?

Across a period from left to right, the elements become less metallic and more nonmetallic in their properties.

What does the atomic mass of an element depend on?

Atomic mass is a value that depends on the distribution of an element's isotopes in nature and the masses of those isotopes.

Explain how you know that no new element with an atomic number less than 100 will be discovered.

Atoms can only have whole protons, and all elements with atomic number less than 100 have been discovered.

Which element in Period 3 besides argon is a gas?

Chlorine

Which isotope of chlorine occurs more often in nature?

Chlorine-35

What categories are used to classify elements on the periodic table?

Elements are classified as metals, nonmetals, and metalloids.

How is the modern periodic table organized?

In the modern periodic table, elements are arranged by increasing atomic number (number of protons).

The atomic mass of iodine (I) is less than the atomic mass of tellurium (Te). But an iodine atom has one more proton than a tellurium atom. Explain how this situation is possible.

Iodine has two less protons than tellurium.

How is air used in making glass bottles?

It pushes the glass to the bottom of the mold.

How do properties vary across a period in the periodic table?

Properties of elements repeat in a predictable way when atomic numbers are used to arrange elements into groups.

Compare the reactions with water of the elements sodium and magnesium.

Sodium reacts violently with water, while magnesium does not react with water unless the water is hot.

Compare the numbers of elements in periods 1, 3, and 5.

There are 2 elements in period 1, 8 elements in period 3, and 18 elements in period 5.

Which type of metals tend to form compounds with distinctive colors?

Transition metals