What basic properties of Mendeleev's periodic table are similar to the current one?

Ahydrogen atom has 1 electron. how many bonds can hydrogen form? a) 1 b) 2 c) 3 d) 4 e) 5

Which statement correctly identifies the scientific question and describes why the question is scientific? question 1 refers to the supernatural.question 2 reflects a moral or social value.question 3 refers to something that can be measured.question 4 reflects a question that can’t be observed.

Consider the following reaction at equilibrium. 2co2 (g) 2co (g) + o2 (g) h° = -514 kj le châtelier's principle predicts that the equilibrium partial pressure of co (g) can be maximized by carrying out the reaction a. at high temperature and high pressure b. at high temperature and low pressure c. at low temperature and low pressure d. at low temperature and high pressure e. in the presence of solid carbon