Cups
Water.
Emotions—love, feelings, relationships, connections. Fluidity, intuition, healing/cleansing. Also powerful and formative. Soft/gentle, or powerful/forceful. Erosion? Feminine, subtle power. Receptive, adaptable, purifying, flowing.
Wands
Fire.
Passion, motivation, energy. Growth as well as destruction. Belief systems, opinions, inspiration
Pentacles
Earth.
Security, safety, groundedness, stability. Career, finances. Tangibility. Physical realm, including a physical relationship.
Swords
Air.
Sometimes subtle, sometimes fierce—but always omnipresent and powerful. The mind, (verbal) communication. Authority, power. Double-edged sword. Damaging but constructive.