Across
- 4. the element under hydrogen
- 5. has 8 valence electrons
- 6. atomic symbol is B and its atomic number is 5
- 8. discovered in 1898 chemical symbol
Down
- 1. has the secound smallest atomic number
- 2. is the very first element of the periodic table
- 3. has 1 valence elctron
- 7. horizonal on the periodic table
- 9. its atomic number is 10 it is a noble gas