Which statement about delta hf is true?
it is zero for any compound in its standard state.
it is positive when the bonds of the product store more energy than those of the reactants.
it is negative when a compound forms from elements in their standard states.
it is zero for any element that is in the liquid state.

Write the symbol for every chemical element that has atomic number greater than 3 and atomic mass less than 12.0 u.

Identify one disadvantage to each of the following models of electron configuration: -dot structures -arrow and line diagrams -written electron configurations type in your answer below. (answer) -dot structures do not show the distribution of electrons in orbitals and take up a lot of space. -arrow and line diagrams take up a lot of space and make it difficult to count electrons. -written configurations make it easy to lose count of electrons and do not show the distribution of electrons in orbitals.

Assignment directions: pick one of the following chemists and perform a bit of research on him/her. answer the following questions. alice hamilton             rosalind franklin marie curie             gertrude b. elion ada yonath             henry cavendish robert boyle             antoine lavoisier mario j. molina             svante arrhenius