Term | Definition |
How did early chemists sort elements into groups? | they used the properties of the elemnts to sort them into groups. |
How did Mendeleev arrangethe elements in his periodic table? | in order of increasing atomic mass. |
In the modern periodic table, how are the elements arranged? | in order of increasing atomic number |
What is the periodic law? | when elements are arranged in order of increasing atomic number, there is a periodic repetition of their phsical and chemical properties. |
What are the three classes of elements? | metals, nonmetals, and metalloids |
Across a period, the properties of elements become what? | less matalic and more nonmatalic |
About 80% of the elements on the periodic table are what? | metals |
Metals are usually good _____ of heat, and ____ currents. | conductors, electrical |
All metals are solids at room temperature except which one? | mercury |
In general, nonmetals are ___ conductors of heat and electrical currents. | poor |
Solid nonmentals are what? | britle |
What are alkali metals? | the elements in group 1A |
What are the elements in group 2A? | alkaline earth metals |
What are the nonmetals of group 7A called? | halogens |
The periodic table usually displays what? | the symbols and names of the elements, along with information about the structure of their atoms. |
How can elements be classified based on electron configuration? | Elements can be sorted ito noble gases, represntative elements, transition metals, or inner transition metals based on their electron configurations. |
What are examples of noble gases? | helium, neon, and argon |
Elements in what groups are often identifies as representative elements? | 1A through 7A |
Transition metals are the group __ elements and are usually displayed in the main body of the periodic table. | B |
What are the elements that appear below the main body of the periodic table? | inner transition metals |
The atomic radius is one half the distance between the ___ of two atoms of the same element when the atoms are joined. | atomic radius |
What is a ion? | an ion is an atom or group of atoms that has a positive or negative charge. |
What is an ion with a positive charge called? | a cation |
An ion with a negative charge is called what? | a anion |
The energy required to remove an alectron from an atom is called what? | ionization energy |
Ionic size tends to ____ from top to bottom within a group. | increase |
Define electronegativity: | the ability of an atom of an element to attract electrons when the atom is in a compound. |
In general, electronegativity values _____ from top to bottom within a group. | decrease |
What are the four blocks? | s block, p block, d block, f block |
How can positive and negative ions form? | when electrons are transfered between atoms. |
When is ionization energy measured? | when an element is in it's gaseous state. |