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?

Aleaky 10-kg bucket is lifted from the ground to a height of 15 m at a constant speed with a rope that weighs 0.7 kg/m. initially the bucket contains 45 kg of water, but the water leaks at a constant rate and finishes draining just as the bucket reaches the 15-m level. find the work done. (use 9.8 m/s2 for g.) show how to approximate the required work by a riemann sum. (let x be the height in meters above the ground. enter xi* as xi.) lim n → ∞ n (9.8)(45−3 xi) i = 1 δx express the work as an integral. 0 dx evaluate the integral. (round your answer to the nearest integer.) j