Organizing the Elements

Some elements have similar chemical and physical properties

• true

• false

List some of the things that Mendeleev included on the first set of periodic table cards

Answer explanation

Medeleev wrote each element's melting point (M.P), density and color on individual cards. He also included the elements atomic mass and the number of chemical bonds it could form.

Tags

NGSS.MS-PS1-1

The ______ is the average mass of all of the isotopes of an element

Answer explanation

The atomic mass is the average mass of all the isotopes of an elememt

Why was Mendeleev able to predict the properties of elements that had not yet been discovered?

Answer explanation

Since there were gaps in the sequence of elements when they were arranged by patterns of properties, Mendeleev was able to predict the properties of elements that had yet to be discovered.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

The present day periodic table is arranged in order of atomic mass

• true

• false

Atomic numbers on the periodic table increase from

• right to left

• top to bottom

• left to right

• bottom to top

The number of protons in an atoms nucleus is the

The horizontal rows in a periodic table are called

• periods

• rows

• columns

• groups

The elements of the modern periodic table fall into 18 vertical columns, or ______.

How are elements formed into Groups?

Answer explanation

These groups, sometimes known as families, consist of elements with similar characteristics.

For example, elements in Group 1 are metals that react violently with water.