Blended learning combines traditional classroom methods with online educational tools, offering a flexible and effective learning experience. One key benefit is that it allows students to learn at their own pace. They can review lessons online, revisit difficult topics, and access materials anytime, which enhances understanding and retention. Additionally, blended learning promotes student engagement through interactive activities like quizzes, videos, and discussions. It also encourages self-discipline and time management skills, as students are responsible for completing online tasks independently. For teachers, it provides valuable tools to track student progress and tailor lessons to individual needs. Furthermore, blending face-to-face instruction with digital content helps create a more personalized and modern education system. In short, blended learning offers the best of both worlds by combining the strengths of traditional and digital learning environments to improve overall educational outcomes.

a) Cấu hình electron của Li: $1{\mathrm{s}}^{2}2{\mathrm{s}}^1$

Do Li có 1 electron ở lớp cuối cùng, 2 lớp electron, số hiệu nguyên tử là 3

=> Thuộc ô thứ 3, chu kì 2, thuộc nhóm IA

b)

Các nguyên tử đồng vị bền: ${}^{3}Li{,}^{3}Li$

=> ${\overline{A}}^{Li}=\genfrac{}{}{0ex}{}{92,5.7+7,5.6}{100}=6,925\left(g\right)$

c) $n^{Li}=\genfrac{}{}{0ex}{}{0,554}{6,925}=0,08\left(mol\right)$

=> Số nguyên tử Li: $0,08.6,02.10^{23}=4,816.10^{22}$ (nguyên tử)

=> Có 4,816.1022 quả cầu