Chemistry 6.1 "Organizing the Elements"
Where can you find metalloids on the periodic table?
Along the "staircase line" separating the metals from the nonmetals.
Why are there more elements in higher numbered periods?
There are more orbitals in higher energy levels.
How did Mendeleev organize his periodic table?
Mendeleev arranged the elements in his periodic table in order of increasing atomic mass.
How many periods/rows are in the periodic table?
7
What percentage of the periodic table consists of metals?
80%
Each period corresponds to what?
A principal energy level.
How did chemists begin to organize the known elements?
Early chemists used the properties of elements to sort them into groups.
How was Mendeleev's periodic table organized?
Elements in a periodic table were arranged into groups based on a set of repeating properties.
What is the general characteristic of nonmetals at room temperature in contrast to sulfur and phosphorus?
Gas
Metal
Generally good conductors of heat and electric current.
Metalloid
Generally have properties that are similar to those of metals and nonmetals.
How is the modern periodic table organized?
In the modern periodic table, elements are arranged in order of increasing atomic number.
What is the only metal that is not a solid at room temperature?
Mercury (Hg)
Which class of metal can have the characteristic of either a metal or a nonmetal depending on the conditions?
Metalloids
What class of element takes up most of the periodic table?
Metals
Which class of element is able to dis-form and not break (malleable)?
Metals
Which class of elements have a high luster and sheen due to its ability to reflect light>
Metals
Do all of the elements in a period have similar chemical and physical properties when moving from left to right?
No; however, when moving from period to period they do nd that is how all of the elements with similar chemical and physical properties end up in the same column or group.
When you move across a period do the elements become more metallic or non metallic?
Nonmetallic
Which class of the elements has a varying of physical properties making it hard to classify them?
Nonmetals
What was wrong with the triad system?
One element in each triad tended to have properties with values that fell midway between those of the other two elements.
Nonmetal
Poor conductors of heat and electric current.
What method helped discover more of the elements of the world.
Scientific method
Why is it faulty to place chemicals in order from decreasing to increasing atomic mass?
Some elements can't follow that rule due to their chemical properties which put them in a group with different elements. Due to this, they cannot go in order of their atomic mass.
What helped scientists organize the modern periodic table?
The discovery about the structure of atoms and their atomic numbers; this was discovered by Henry Moseley.
Why couldn't early chemists discover all of the elements?
They couldn't isolate the elements from the compounds
What are the three broad classes of elements?
Three classes of elements are metals, nonmetals, and metalloids.
How were elements organized in the classification system?
Triads; this is a set of three elements with similar properties. This was determine by the scientist J.W. Dobereiner.
Periodic Law
When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties. The arrangement of the elements into periods has an important consequence. Elements that have similar chemical and physical properties end up in the same column in the periodic table.
