1. Who was the first person to create a periodic table? When? 2. What is the modern periodic table?

3. Compare and contrast the periods and groups of the modern periodic table.

4. In the modern periodic table (found in the back of your agenda), find the element named lead (Pb). How many protons do atoms of lead have? To which class of elements does lead belong?

5. Most of the elements on the periodic table belong to what class of elements.

6. Which groups of the modern periodic table contain elements that are classified as metalloids?

The atomic radius of sodium is 186 pm and of chlorine is 100 pm. the ionic radius for na+ is 102 pm and for cl– is 181 pm. in going from na to cl in period 3, why does the atomic radius decrease while the ionic radius increases? a. the inner electrons in the sodium cation shield its valence electrons more effectively than the inner electrons in the chloride anion do. b. the inner electrons shield the valence electrons more effectively in the chlorine atom than in the chloride anion. c. the outermost electrons in chloride experience a smaller effective nuclear charge than those in the sodium cation do. d. the outermost electrons in chloride experience a larger effective nuclear charge than those in the sodium cation do. e. monatomic ions are bigger than the atoms from which they are formed.

What is the solubility of substance?

What is a main difference between a mixture and a pure substance? a mixture is only a liquid, but a pure substance can be in any state.a mixture looks the same throughout, but a pure substance does not.1 a mixture can vary in composition, but a pure substance has a set composlo a mixture can be made up of a single compound, but a pure substance car