Infrared radiation has _____________wavelengths and ________________frequencies than ultraviolet radiation

LONGER wavelengths and LOWER frequencies.

Those are the correct two terms you want. Wavelengths are an actual distance, so the terms "short" or "long" are applicable. Frequencies are per-second rates, expressed in Hertz, so the terms higher or lower apply to them.

First gap= Longer
Second gap= Shorter

longer, lower

higher and then lower