Can someone tell me what an isotope is in your own words, please don't copy and paste

Which atom or ion is the largest? a. k b. k+ c. ca d. ca2+ e. li

How do you know when a chemical reaction has occurred

Astudent completes a titration by adding 12.0 milliliters of naoh(aq) of unknown concentration to 16.0 milliliters of 0.15 m hcl(aq). what is the molar concentration of the naoh(aq)? 1)5.0 m 2)0.20 m 3)0.11 m 4)1.1 m