Periodic Table 1

In the modern Period Table the elements are arranged in order of increasing

• atomic number

• mass number

• oxidation number

• valence number

Answer explanation

• Elements of the periodic table are arranged in order of increasing atomic number.

• A Period is a Horizontal row.

• A Group is a Vertical Column.

• The atomic number indicates how many protons there are in a specific atom.

The element in Period that has the lowest first ionization energy is

• an alkali metal

• an alkaline earth metal

• a halogen

• a noble gas

Answer explanation

Ionization energy is the energy required to remove an electron from a specific atom.

Moving from left to right across the periodic table, the ionization energy for an atom increases.

The more protons in the nucleus, the stronger the attraction of the nucleus to electrons.  This stronger attraction makes it more difficult to remove electrons. 

In Period 2 as the elements are considered from left to right there is a decrease in

• ionization energy

• atomic mass

• metallic character

• non-metallic character

Answer explanation

Group 1 elements are most metallic.

A metal is an element that is a good conductor of heat and electricity. Metals are also malleable, which means that they can be hammered into very thin sheets without breaking. They are ductile, which means that they can be drawn into wires.

As the elements of Group 1 are considered in order of increasing atomic number. The atomic radius of each successive element increases. This primarily due to an increase in the number of

• neutrons in the nucleus

• electrons in the outermost shell

• unpaired electrons

• principal energy levels

Answer explanation

There are seven horizontal rows of the periodic table, called periods.

Elements in the same period have the same number of energy shells.

The reactivity of metals in Group 1 and Group 2 generally increase with

• increased ionization energy

• increased atomic radius

• decreased nuclear charge

• decreased mass

Answer explanation

As Atomic radius increases valence electrons are further away from the attraction of the positive nucleus. Therefore the pull on these valence electrons become less as the atomic radius increases. In turn the ionization energy is also less.

Which element listed has the least metallic character?

• Na

• Mg

• Al

• Si

Which of the following has the largest atomic radius?

• Na

• K

• Mg

• Ca

Which of the following Group 2 elements have the lowest first ionization energy?

• Be

• Mg

• Ca

• Ba

Answer explanation

Ionization energy decreases as you go down a group.

Its easier to lose valence electrons.

Which symbol represents an Alkaline Earth Element?

• Na

• Mg

• Ne

• Ag

Answer explanation

Alkaline Earth Metals are found in Group 2 of the Periodic Table.

Group 2 elements have 2 valence electrons.

Alkaline Earth Metals are in Group

• 1

• 2

• 3

• 17