#1: what was the key characteristic by which dmitri mendeleev arranged his periodic table?

a. increasing atomic number

b. electron configuration

c. decreasing atomic number

d. increasing atomic mass

**my d. increasing atomic mass

is that right?

When the chemicals iron sulfide (fes) and hydrochloric acid (hcl) are combined, bubbles appear from the mixture. 1. does the appearance of bubbles indicate a physical or chemical change? 2. why do the bubbles indicate this change? 3. what property is this?

What is the name of the enzyme that forms at the start of transcription?

The footprints of a dinosaur and the burrow of an ancient shrimp are examples of which kind of fossils