1s²
Explanation:
The predicted electron configuration of Helium 1s².
Helium is an element with atomic number of 2. it is located on the last group on the periodic table.
- Electron distribution into the energy levels or sublevels of atoms can be shown using electronic configurations.
Here, the two electrons in Helium fills the first energy level with s-sublevel first.
The maximum number of electrons in the sub-level is 2: this gives the 1s² configuration.
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Antoine Lavoisier proved that oxygen is required for material to burn. Without oxygen, the fire goes out which is easily testable.
Answer:
metallic bonding
Explanation:
Metallic bonding is bonding where electrons exist as "sea of electrons" meaning they can go anywhere in the structure and are not localized in specific place like covalent bonds are sometimes.
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atoms are made of 3 types of sub atomic particles- protons, neutrons and electrons
from these 3 particles, electrons are responsible for participating in chemical bonds. therefore chemical properties of elements are based on the number of electrons present.
valence electrons are the number of electrons in the outermost energy shell that are involved in chemical bonds.
atoms with same number of valence electrons are grouped in to columns called groups.
therefore elements of the same group have same number of valence electrons, hence similar chemical properties.
from the options given
only Be and Mg belong to the same group they both belong to group 2 with 2 valence electrons
therefore Be and Mg have similar chemical properties
answer is
1) Be and Mg