Generation II

Generation II (also called the metal or precious metal generation) is the second generation of Pokémon games, and sequels to the original Generation I games Red and Green (Red and Blue for international players).

Generation II was the first Generation where Pokémon began to expand, introducing 100 new Pokémon which could not be found in the original Generation I games. Many of these Pokémon expand the evolution families of older Pokémon, while a majority of them are brand-new evolutionary families.

These games were initially called "Pocket Monsters 2". Generation II events occur three years after Generation I, and occur simultaneously with the events of Generation IV.

Starter Pokemon
The three Starter Pokemon in Gen. II are;

Chikorita - Grass

Cyndaquil - Fire

Totodile - Water

Advances in gameplay
Generation II kept the system from Generation I in almost every aspect, but added new features to the series, many of which have been kept in every Generation afterward.
 * 100 new Pokémon.
 * 8 new Gym Leaders.
 * 2 new Pokémon Types: (Japanese: あくタイプ Evil type) and  (Japanese: はがねタイプ Hagane type).
 * Pokémon now have genders. Some Pokémon are exclusively female (ex. Chansey), exclusively male (eg. Hitmonchan) or without gender (Magnemite).
 * Pokémon Breeding. Some Pokémon (eg. Pichu) can only be obtained through breeding. Some moves can also be learned exclusively through breeding.
 * The Pokémon maintain a degree of happiness. Some Pokémon only evolve when reaching a certain degree of happiness (eg. Eevee).
 * Backward compatibility with Red, Blue and Yellow versions.
 * Internal clock: Included for the first time. Times of day are also separated into Morning, Day and Night.
 * Different Pokémon are encountered at different times and certain events only happen during certain days of the week.
 * An EXP bar was added to the battle screen to show how much is needed to level up.
 * The SPECIAL stat was separated into Special Attack and Special Defense.
 * The Pokémon may carry items equipped that they can use themselves in battle Pokémon.
 * Berries are introduced (in the third generation would be replaced by other types) and differentiate between objects that the Pokémon can be used by themselves in combat and those who do not.
 * Certain Pokémon are now able to evolve when traded while holding a particular item.
 * First appearance of Pokérus.
 * A new feature called the PokéGear appears that has the capabilities of a mobile phone, allowing trainers to challenge you to a rematch, and radio, with various radio shows and music.
 * Some Pokémon are updated with new types or characteristics (Magnemite and Magneton become / type, for example).
 * In-battle weather effects are added.
 * -type attacks are super effective against Pokémon.  attacks do normal damage to  Pokémon,  attacks now do damage to the  Pokémon.  attacks are now ineffective against  Pokémon.
 * Some attacks have changed their type, e.g. Bite changed from to  type. New movements are added, highlighting the  to balance the weaknesses of -type Pokémon.
 * A new evolution stone, the Sun Stone was added.
 * New evolutions for Pokémon that previous didn't evolve (eg. Scyther) and alternative evolutions for others (Eevee, Gloom, Poliwhirl).
 * For the first time, Legendary Pokémon appear as version mascots, each obtained earlier in their respective game than the other.
 * The backpack where objects are kept were separated into different compartments.
 * New types of Poké Balls, many of them created from Apricorns.
 * The ability to find differently colored Pokémon, Shiny Pokémon, is added.
 * Possibility to visit Kanto years after Red/Blue/Yellow, with trainers with high levels, the opportunity to complete the eight Gyms in Kanto (being 16 in total in the game), and the ability to fight both Blue, or the rival from the previous generation and Red, the protagonist of the previous generation.
 * In Crystal, a female player character, Kris, can be chosen for the first time.
 * In Crystal, moving sprites are given to opposing Pokémon and Pokémon on their stats page.
 * Gold, Silver and Crystal feature infared connectivity to the Pokémon Pikachu and Pokémon Pikachu 2 pedometer using the mystery gift feature.

Trivia

 * The Pokémon of the second Generation have the Pokédex numbers #152 - #251. This set of Pokémon first debuted in Pokémon Gold and Silver.
 * Generation II often refers to Pokémon Gold and Silver, as they are the second set of Pokémon Games.
 * They also released Pokémon Crystal and the release of the Anime movie Pokémon 2000.
 * Generation II is the currently the only generation where none of the starters or their evolved forms were dual types.
 * The European releases of the Gold and Silver games featured no connectivity to the Pokémon Pikachu 2

Primera generación