In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Since the incidence and severity of specific adverse effects differ among the various atypicals , the clinician should carefully consider which side effects are most likely to lead to the individual ' s dissatisfaction and noncompliance before choosing an antipsychotic for a particular patient .
### Output Text:
Since the incidence and severity of specific adverse effects differ among the various atypicals , the clinician should carefully consider which side effects are most likely to lead to the individual ' s dissatisfaction and noncompliance before choosing an antipsychotic for a particular patient . 