Periodic Table

Mendeleev was the first person to arrange the elements into a table. How did he arrange the rows?

• alphabetical 

• density

• melting point

• atomic mass

All the elements that are in red and that make up the staircase are called...

• metals

• nonmetals

• metalloids

• noble gases

Answer explanation

The elements in red that form the staircase on the periodic table are called metalloids. They exhibit properties of both metals and nonmetals, making them distinct from the other categories listed.

Tags

NGSS.MS-PS1-1

Which of the following elements is in period 2?

• K

• H

• O

• Ca

Answer explanation

Oxygen (O) is in period 2 of the periodic table, while potassium (K) and calcium (Ca) are in period 4 and hydrogen (H) is in period 1. Therefore, the correct answer is O.

Tags

NGSS.MS-PS1-1

All of the noble gases have similar properties. Which element has similar chemical properties of the noble gas Argon (Ar)?

• Iodine

• Oxygen

• Fluorine

• Xenon

Answer explanation

Xenon (Xe) is a noble gas like Argon (Ar) and shares similar chemical properties, such as being inert and having a full valence shell. The other options (Iodine, Oxygen, Fluorine) are not noble gases and have different reactivity.

How many valence electrons do all of the Group 2 Alkaline Earth Metals have?

• 1

• 2

• 5

• 7

• 8

Answer explanation

All Group 2 Alkaline Earth Metals have 2 valence electrons. This is because they are in Group 2 of the periodic table, which indicates they have two electrons in their outermost shell.

This group is made of the MOST reactive metals.

• Transition metals

• Metalloids

• Alkali Metals

• Alkaline Earth Metals

Answer explanation

The Alkali Metals, found in Group 1 of the periodic table, are the most reactive metals due to their single valence electron, which they readily lose to form positive ions. This makes them highly reactive compared to other metal groups.

This group does NOT react with anything ever, they are already happy.

• Metals

• Transition Metals

• Noble Gases

• Halogens

Answer explanation

Noble gases, such as helium and neon, are chemically inert and do not react with other elements because they have a full valence shell, making them stable and 'happy' without needing to bond.

These elements are really bad at conducting heat/electricity.

• Non-metals

• Transition Metals

• Metals

• Metalloids

Answer explanation

Non-metals are poor conductors of heat and electricity due to their lack of free electrons, unlike metals and metalloids which have better conductivity. Transition metals are also good conductors, making non-metals the correct choice.

Which color on the image of the periodic table corresponds with the transition metals.

• red

• black

• blue

• orange

Answer explanation

In the periodic table, transition metals are typically represented in blue. This color coding helps to easily identify these elements, which are located in the central block of the table.

metalloids (semimetals)

• Elements that occur in vertical columns on the periodic table.

• an element that has both metallic and nonmetallic properties

• not able to conduct heat or electricity, little to no metallic luster

• found in group one of the periodic table; highly reactive

Answer explanation

Metalloids, or semimetals, possess characteristics of both metals and nonmetals, making the correct choice 'an element that has both metallic and nonmetallic properties'. The other options describe different categories of elements.