Identify the smallest unit of an element

The particles of an ice cube at 0°c (represented by the blue circles) come in contact with the particles of juan’s hand at 37°c (represented by the orange circles). which diagram correctly represents the temperature of the two substances and the direction of heat flow?

What type of nuclear decay causes the atomic number of an element to increase by 1?

At very high pressures, gases become and will eventually a) more dense; become hotter b) more dense; change to a liquid or solid c) less dense; combust d) less dense; turn into a liquid