Which of the following best describes why the atomic model has changed repeatedly over the past 200 years? 1. most of the models were huge mistakes. 2. very few people thought the models were valid. 3. the models were known to be incomplete and needed to be fixed. 4. the results of further experimentation to revise and improve the model.

Me i dont know what to do! the table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 10 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of the two atoms? both are unreactive. both are highly reactive. a is unreactive and d is reactive. a is reactive and d is unreactive.

Which metal exist in liquid state and can be cut with knife ?

What substance has a mass of 9.5g and volume of 2.1cm^3