Symbol-atomic number-mass number- Ca. 20. (blank)

#neutrons-#protons-#electrons-
(blank) 20. 18

atom or ion (include charge)
+2 Cation

-isotope or atom
isotope

Astudent is given an assignment to demonstrate diffraction. he takes a photograph of a straw in a glass of water. the straw appears bent at the water level. which best describes this example? a) this is a good example of diffraction. b) this is an example of dispersion and not diffraction. c) this is an example of refraction and not diffraction. d) this is an example of reflection and not diffraction.

Which best describes the first law of thermodynamics as compared to the second law of thermodynamics? a. the first law describes how thermal energy is conserved but not the direction it moves. b. the first law describes the direction thermal energy moves but not how it is conserved. c. the first law describes how thermal energy can be created but not how it can be destroyed. d. the first law describes how thermal energy can be destroyed but not how it can be created.

Directions: count the number of atoms. ar co2 na3po4 so3 nac2h3o2