Write the symbols for three other species, which also have the electron arrangement of 2.8.
To find three other species with the electron arrangement of 2.8, we need to look at the periodic table. The electron arrangement 2.8 refers to the number of electrons in each energy level (shell) of an atom. The first shell can hold a maximum of 2 electrons, while the second shell can hold a maximum of 8 electrons.
Let's start by looking at the second period (row) in the periodic table, as the second shell corresponds to the second period. The elements in the second period have electron arrangements that follow the pattern: 2, 8. So, the first two elements in the second period are:
1. Lithium (Li): The electron arrangement of lithium is 2.1, which means it has 2 electrons in the first shell and 1 electron in the second shell.
2. Beryllium (Be): The electron arrangement of beryllium is 2.2, which means it has 2 electrons in the first shell and 2 electrons in the second shell.
Now, let's move to the third period, which is the next row in the periodic table. The third shell can also hold a maximum of 8 electrons. Here are two elements from the third period:
3. Sodium (Na): The electron arrangement of sodium is 2.8.1, which means it has 2 electrons in the first shell, 8 electrons in the second shell, and 1 electron in the third shell.
4. Magnesium (Mg): The electron arrangement of magnesium is 2.8.2, which means it has 2 electrons in the first shell, 8 electrons in the second shell, and 2 electrons in the third shell.
So, three other species with the electron arrangement of 2.8 are: lithium (Li), beryllium (Be), sodium (Na), and magnesium (Mg).