In Mendeleev’s periodic table, elements with similar properties were grouped __________.

• in the same row
• in the same column
• in diagonal lines that run from top left to the bottom right
• in pairs of two

For which element did Mendeleev correctly predict the properties even before it had been discovered?

• gallium
• hydrogen
• bromine
• aluminum

Answer explanation

Mendeleev called his predicted element eka-aluminum because it was right below aluminum on his table. Because of how his table was organized, he was able to successfully predict some properties of his eka-aluminum. Several years after Mendeleev's prediction, gallium was discovered, and it had almost identical properties to what Mendeleev predicted.

The first elements to be identified were mainly gases.

• True
• False

Answer explanation

The first elements to be discovered were mainly solids.

As the number of known elements grew, so did the need to organize them into groups based on their __________.

• phase state
• color
• properties

Answer explanation

Organizing elements by their properties allowed scientists to predict how known and unknown elements would react chemically.

Tags

NGSS.MS-PS1-2

Which of the following categories did French chemist Antoine Lavoisier use to classify elements?

• gases
• metals
• liquids

Answer explanation

Antoine Lavoisier classified elements into metals, nonmetals, gases and earths.

Which type(s) of information did Dmitri Mendeleev know about each element?

• name
• number of protons
• relative mass

Answer explanation

Dmitri Mendeleev used the name, mass, and properties of each known element to create his periodic table.

Dmitri Mendeleev arranged the elements into rows in order of __________ so that elements with similar properties were in the same column.

• increasing mass
• atomic number
• decreasing mass

Answer explanation

Organizing elements by increasing masses and breaking them into rows is what allowed Mendeleev to start seeing patterns.

A periodic table is an arrangement of elements in columns, based on a set of properties that repeat from row to row.

• True
• False

Mendeleev published the table blank for __________ elements.

Answer explanation

Mendeleev was confident that the gaps in his table would be filled by new elements.

Which two elements have similar properties?

• zinc (Zn)
• chlorine (Cl)
• bromine (Br)

Answer explanation

Elements in the same column (group) will have similar properties.