Astudent takes four samples of a white crystalline solid and places each in a well plate. on top of each sample, she carefully places 20 drops of mystery liquids a, b, c and d. her results for each well are:
the solid dissolves quickly in liquid a.
the solid remains unchanged with the addition of liquid b.
the white solid remains, but dissolves very slowly in liquid c.
when liquid d is added, fizzing occurs and the well becomes warmer.
in which well does a chemical change occur?

Write the chemical formula for a compound that is made of an element from group 1 and an element from group 17

The table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 9 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of tthe table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 9 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.

The fact that the total amount of energy in a system remains constant is a(n)