Semester 2 Science - Periodic Table

How many elements were known around the 1860s?

• about 80

• about 120

• about 60

• about 50

Answer explanation

So it's the 1860s, and about 60 elements are known to mankind, and their atomic weights are mostly known as well.

Who discovered four of the 6 noble gases (neon, argon, krypton, xenon)?

• Sir William Ramsay

• Dimitri Ivanovich Mendeleev

• Henry Cavendish

• Sydney Young

Answer explanation

Sir William Ramsay was a British physical chemist who discovered four gases (neon, argon, krypton, xenon) and showed that they (with helium and radon) formed an entire family of new elements, the noble gases. He was awarded the 1904 Nobel Prize for Chemistry in recognition of this achievement.

Why is the periodic table a great predictable tool?

• Because one can predict how many elements will be discovered in the future and how the periodic table will look like

• Because if one knows the periodic table one knows what other elements will be discovered in the future

• Because if one knows where an element is in the periodic table than one knows everything about that element

• Because if one knows where an element is placed in it one can know a lot about the behaviour of the element

Answer explanation

What makes the periodic table really invaluable is its use as a predictive tool. You can predict a lot about the chemical behavior of an element if you know where it is on the periodic table.

Which language the chemical symbol of lead (Pb) comes from?

• Italian

• Latin

• French

• English

Answer explanation

Many of the chemical symbols are derived from the English name for the element, but some come from other languages. For example, the symbol for silver is Ag, from the Latin word argentum. The symbol for lead is Pb, from the Latin word plumbum.

What is above and what is under the element's chemical symbol?

• Above is the element's atomic number and below are the full name and its atomic mass

• Above is the element's atomic mass and below are the full name and its atomic number

• Above is the element's full name and below are the atomic mass and its atomic number

• Above is the element's atomic mass and number and below is the element's full name

Answer explanation

Above the chemical symbol is the atomic number of the element, and below the symbol are the full name of the element and its atomic mass.

Where does each element's unique atomic number comes from?

• From the number of neutrons in the nucleus of its atom

• From the number of neutrinos in the nucleus of its atom

• From the number of protons in the nucleus of its atom

• From the number of electrons in the nucleus of its atom

Answer explanation

Notice that the atoms are listed in order of increasing atomic number, as you read the periodic table from left to right, top to bottom. Each element has a unique atomic number - that’s the number of protons in the nucleus of the atom.

What do the "periods" (7 horizontal lines) in the periodic table correspond to?

• They correspond to the metalloids

• They correspond to if the element is a metal or a non-metal

• To different energy levels occupied by electrons

• To different energy levels occupied by protons

Answer explanation

There are 7 horizontal rows in the periodic table. These rows are called PERIODS. Each row corresponds to a different energy level occupied by electrons.

What is the periodic law?

• The periodic law states that metals and nonmetals can be placed next to each other in the periodic table

• The periodic law is the way that periods, groups and families are repeated

• The periodic law states that the groups and periods are in order

• The periodic law is a periodic repetition of some characteristics of the elements

Answer explanation

If you arrange elements by atomic number, a pattern emerges. There is a periodicity, or a repeating, of certain characteristics. For example, every so often, an inert gas appears. Right next to it will be an element that reacts violently with water. This periodic repetition is known as the PERIODIC LAW. This is the basis for organizing the elements in the Periodic Table into columns.

What do elements in the same period share something in common?

• They share their energy shell

• They share their atomic number

• They share their atomic mass

• They share their groups

Answer explanation

The rows going across from left to right are “periods”. Elements in the same period all share something in common—they have the same number of energy shells. Each new period row represents a new shell. Elements in the first period have one shell, and as we go down the shells increase. Hydrogen is in the first period; it has one shell. Potassium is in the fourth period, and has four energy shells—as do all the other elements in this period.

What are the 4 main types of chemical bonds?

• Nitrogen, ionic, metallic & covalent bonds

• Hydrogen, ionic, metallic & covalent bonds

• Hydrogen, ionic, non-metallic and covalent bonds

• Hydrogen, electric, metallic and ionic bonds

Answer explanation