The properties of elements reoccur periodically based on their
metallic qualities.
The properties of elements reoccur periodically when arranged
by increasing atomic number.
The properties of elements reoccur periodically when arranged
by increasing atomic mass.
The periodic table arranges elements into periods and groups.
When atoms react, they often lose, gain, or share electrons to form a more stable version of themselves. For example, alkali metals such as Na lose their outer shell electron in their reactions to form compounds. The electron configuration of alkali metals would then resemble those of which group of the periodic table in the compounds they form?
2
1
17
18
In the periodic table hydrogen is placed and Group 1 and helium is placed in Group 18. The most likely reason for this is:
Hydrogen and helium are both metals.
Hydrogen has one outer shell electron and helium has 8 electrons in its valence shell.
Hydrogen and helium are both gases
Hydrogen has one outer shell electron and helium has a full valence shell of electrons.
The metallic character of elements _____ across a period from left to right. Metals are good conductors of ______.
decreases, heat
decreases, metalloids
increases, electricity
remains the same, luster
An early arrangement of the then known elements was proposed by a British scientist John Newlands, which he called the Law of Octaves. Like other scientists at the time, Newlands arranged the elements in order of increasing atomic mass and noted that every eighth element had similar physical and chemical properties.
In the modern Periodic Table, Mendeleev also used the atomic mass to group elements, but what did he do when he came across elements that didn't match up? Pick 2
Mendeleev didn't arrange the elements. He stopped when he had a mismatch.
Mendeleev left gaps in the table for elements that hadn't been discovered yet.
Mendeleev arranged the elements based on the number of electrons.
Mendeleev arranged his table by atomic mass, but broke the rule so that elements with similar properties would be in the same column.