1 Hydrogen 1s1
2 Helium 1s2
3 Lithium 2s1
Answer:
Atoms are composed of a central nucleus which is surrounded by orbiting <u>Electrons</u>.
Explanation:
The word Atom is derived from atomos meaning indivisible particle. An atom is a very small sized particle and its size is approximately 100 picometers.
Atoms are composed of a Nucleus which contains protons and neutrons and the nucleus is surrounded by orbiting electrons. Also, the nucleus is positively charged due to +ve protons and the electrons revolving around nucleus are -vely charged making overall atom neutral in nature.
Atoms react with another atoms due to the presence of valence electrons present in the valence shell of an atom. The valence electrons would make a covalent bond by mutually sharing the electrons or it may form an ionic bond by gaining and loosing valence electron.
Phenolphthalein turn pink in basic solutions.it turn colourless in acid solution.
Hence options(1)is correct
Answer:
A double displacement reaction or double replacement reaction.
Explanation:
9.74x 2351 that's the answer
